Learning purpose

The word "reasonable" performs several distinct legal functions within construction contracts and associated decision-making provisions. It may prescribe an objective standard of workmanship, professional care, cost, time or response. In a different provision, the same word may qualify the exercise of a contractual discretion entrusted to one party. The word may also form part of a valuation or extension-of-time mechanism which calls for judgement upon an incomplete record. Treating all of those expressions as if they imposed the same legal test produces defective submissions and indefensible decisions.

Successful completion requires the learner to identify the contractual function performed by the word; distinguish objective reasonableness from the controls governing a discretionary decision; determine whether the relevant clause confers a genuine choice or merely requires the application of fixed machinery; examine the wording, purpose, factual record and evidential gaps; separate the decision process from the resulting conclusion; and prepare a reasoned extension-of-time decision which can be traced to the contract and the available evidence.

1. Objective standards of reasonableness

An objective standard asks what ought reasonably to have been done, achieved, allowed, charged or concluded in the circumstances. The answer is not governed by the personal view of the party required to meet the standard. For a contractor undertaking to exercise reasonable skill and care, the measure is the care expected from the relevant professional or trade practitioner performing that work. Where a party promises to complete within a reasonable time, the applicable period is determined from the contractual circumstances. A term requiring payment of a reasonable price directs attention to an objectively justified price. The court or tribunal determines the standard and applies it to the proven facts.

Objective reasonableness remains sensitive to the governing contract and the complete factual setting in which performance occurred. It does not permit an adjudicator, arbitrator or judge to select an outcome by instinct. A reasonable period for responding to a straightforward request for an identified drawing may differ from the period reasonably required to assess a substantial extension-of-time submission containing several delay events and competing programmes. Reasonable skill and care in checking a temporary works calculation depends upon the professional task undertaken, the applicable contractual requirements, the information made available and the risks which a competent practitioner ought to recognise. Although the standard is objective, its content is established through the particular obligation and surrounding circumstances.

The contractual words must therefore be analysed carefully before the supporting factual and expert evidence is assembled. A requirement to act "within a reasonable time" differs materially from an obligation to act "within 14 days". The former requires the applicable period to be determined objectively; the latter ordinarily requires calculation of a fixed period. By comparison, "reasonable endeavours" governs the efforts which a party must make, whereas an obligation to achieve a defined output governs the required result. An obligation to exercise "reasonable skill and care" does not ordinarily convert every design obligation into a guarantee of success, but a separate incorporated performance requirement may impose an outcome alongside the professional standard. The word cannot be detached from the noun, verb and contractual subject which it qualifies.

Objective reasonableness also differs from a general power to improve an unsatisfactory bargain. Commercial parties may agree strict duties, fixed deadlines and express risk allocations which leave no room for a freestanding reasonableness qualification. A claims specialist must not add the word because a result appears harsh. The inquiry begins with the language which the parties adopted, construed within the contract as a whole. An express objective standard must be applied; a limitation which the contract does not contain cannot be introduced merely to redistribute the consequences after the event.

The Court of Appeal drew the distinction precisely in Socimer International Bank Ltd v Standard Bank London Ltd [2008] EWCA Civ 116. Rix LJ explained at paragraph 66 that reasonableness used for reasonable care, a reasonable price or a reasonable time is guided by objective criteria. In that class of case, the court or tribunal determines the objective answer by applying the agreed standard. By contrast, the rationality controls imposed upon a contractual discretion leave the decision with the contractual decision-maker. This distinction determines the evidence required, the permissible intensity of review and the remedy which may follow.

Consider a subcontract which requires temporary access to remain available for a "reasonable period after completion of the lifting operation". The period cannot be established by asking only what the main contractor believed was sufficient. Determining that period requires evidence of the access purpose, demobilisation operations, safe removal sequence, information given when the access was planned, later changes and the time which competent performance required. If the tribunal concludes that seven days were reasonably required, the main contractor cannot defend removal after two days merely by proving an honest belief that two days were enough.

The same objective approach applies when the contract requires assessment of a reasonable construction cost or expenditure. Records must show the work performed, resources reasonably required, rates, productivity, available alternatives and the contractual basis of valuation. A claimed expenditure does not become reasonable merely because it was actually incurred. Conversely, the lowest theoretical expenditure is not necessarily the only reasonable one. The objective standard admits a permissible range where several competent courses were available, but the conclusion still belongs to the tribunal applying the contract, rather than to the party whose account is under review.

Proof must be directed to the disputed contractual standard rather than an assumed or preferred standard. Contemporary programmes, instructions, resource records, correspondence, technical submissions, progress photographs and expert evidence may each assist, but their value depends upon the issue. An expert opinion which begins from the wrong contractual test cannot cure that error through technical detail. A delay model may demonstrate the effect of an event under stated assumptions, yet it does not establish that those assumptions correspond with the project record. Objective reasonableness calls for a reasoned conclusion from the contractual obligation and admissible evidence, not an unexamined reliance upon the most elaborate document.

2. Contractual discretion, rationality and proper purpose

A contractual discretion exists where the agreement entrusts a choice, judgement or evaluative decision to a named party. Common examples include a power to approve, withhold consent, value an asset, allocate a bonus, determine whether a circumstance is dangerous or assess an interim entitlement. The decision may affect both parties while the power is placed in the hands of one. English law does not ordinarily treat that allocation as permission for arbitrary choice. Depending upon the wording and context, limitations may be implied to ensure that the power is exercised honestly, in good faith, for its contractual purpose and rationally.

Those controls do not ordinarily replace the contractual decision-maker with the court. The court reviews whether the power was abused, not whether it would have made the same decision. A result may fall within a rational range even though another evaluator would have selected a different figure. That permitted latitude reflects the parties' contractual allocation of responsibility for making the relevant decision. It also explains why a challenge framed only as "the decision was unreasonable" is inadequate. The claimant must identify the applicable control and the defect said to engage it, such as an irrelevant consideration, failure to consider a material matter, absence of necessary enquiry, improper purpose, arbitrariness or a conclusion outside the rational range permitted by the evidence.

In Socimer, the contract required a seller bank to value designated assets following termination. Rix LJ addressed the limitations upon a contractual power which could affect both parties. At paragraphs 60 to 66, the judgment examined honesty, good faith, genuineness, proper purpose and the absence of arbitrariness, caprice, perversity and irrationality. The Court of Appeal rejected the proposition that the bank's valuation obligation should instead become an objective duty to arrive at the value which the court considered proper. Standard Bank succeeded on the issues argued, and the first-instance decision based upon the objective test could not stand.

The distinction was adopted by the Supreme Court in Braganza v BP Shipping Ltd [2015] UKSC 17. Under the employment contract, a death benefit was payable unless, in the employer's opinion, the employee's death resulted from his wilful act. Following its investigation, the employer concluded that the chief engineer had probably committed suicide. Lady Hale examined the controls applicable when one contractual party makes a decision affecting both parties. At paragraphs 17 to 32, the judgment confirms that the content of the implied limitation depends upon the contract and context, and distinguishes review for rationality from the imposition of a wholly objective standard.

The reasoning commonly described as the Braganza duty contains attention to both process and outcome. To satisfy the process requirement, the decision-maker must address the correct contractual question, consider relevant matters, exclude irrelevant matters and undertake enquiries which the circumstances reasonably require. Any resulting conclusion must remain within the range rationally available upon the material considered. Those process and outcome requirements operate as connected controls upon the exercise of the contractual power. A procedurally defective decision may nevertheless have reached a plausible outcome, but the plausibility of the result does not repair a process which omitted a material possibility. Equally, a carefully recorded process cannot validate a conclusion which the evidence could not rationally support.

The Supreme Court did not prescribe an administrative-law code for every commercial decision. Lady Hale stated at paragraph 31 that the contractual context controls the intensity of review and that the court should not undertake a judicially microscopic examination. At paragraph 30, she distinguished cases in which the contract calls for an objectively reasonable price or term from cases in which the decision remains entrusted to a party. Claims specialists should therefore resist both extremes: an apparently discretionary power is not necessarily unfettered, but its exercise is not automatically reheard as if the original decision-maker had never acted.

The judgment in Braganza also demonstrates how a contractual decision-maker should approach evidential probability. At paragraphs 33 to 36, Lady Hale addressed proof on the balance of probabilities and explained that an inherently improbable event may require more cogent evidence as an evidential matter, without changing the legal standard of proof. The employer's inquiry had not adequately considered the real possibility of an accident. At paragraphs 51 to 60, Lord Hodge identified the absence of a sufficient evidential basis for the conclusion that suicide was more likely than accidental disappearance. Having identified those defects in the employer's conclusion, he would allow the appeal at paragraph 64, and the majority did so, Lord Neuberger and Lord Wilson dissenting.

The lesson for construction decisions is not that an adverse conclusion must be supported beyond reasonable doubt. Lady Hale confirmed at paragraph 34 that there is no sliding scale of probability commensurate with the seriousness of the subject matter or the consequences of the decision, and that the only question is whether something is more likely than not to have happened. What paragraph 35 recognises is a different point: the more inherently unlikely an event, the more cogent the evidence required to persuade the decision-maker that it has happened. That distinction was restated in Jones v Birmingham City Council [2023] UKSC 27, where the Supreme Court held at paragraph 51 that inherent improbability may require more cogent evidence, while rejecting any general rule that the seriousness of an allegation, or of its consequences, does so. In practice, a conclusion that progress records were deliberately falsified must be tested against the evidence and the inherent probabilities of the case, without raising the standard because the allegation is grave.

A disciplined decision record should identify the source and limit of the power; the contractual question; the material reviewed; factual findings; unresolved matters; enquiries made; considerations included and excluded; the reasoning from facts to conclusion; and the effect of the decision. Such a contemporary record serves an evidential and legal purpose if the conclusion is later challenged. It permits the parties and any later tribunal to distinguish a genuine contractual evaluation from an unexplained assertion. The record also guards against reconstruction after the dispute has matured, when reasons not considered at the time may be added to defend the result.

3. Genuine discretion distinguished from fixed contractual machinery

Words such as "may", "determine", "assess" or "reasonable" do not establish by themselves that a party possesses a legally protected discretion. Certain clauses confer a real choice between two or more outcomes permitted by the contractual language. Other provisions prescribe machinery which, when the required facts are established, yields the contractual answer. In the latter case the party applying the machinery is either right or wrong. The answer does not acquire a margin of permissible error merely because one party performs the calculation or sends the notice.

This distinction was examined in Mid Essex Hospital Services NHS Trust v Compass Group UK and Ireland Ltd [2013] EWCA Civ 200. The contract contained a performance regime under which service failures generated points and deductions. Jackson LJ accepted at paragraph 136 that a contractual discretion affecting both parties may require implied restrictions to prevent uninhibited whim. At paragraphs 137 to 140, however, he distinguished that situation from the application of express contractual machinery. Where the contract and formula determine the result, the party applying them does not exercise a discretion of the kind controlled by the implied rationality term.

The legal distinction changes the form and substance of any later challenge to the resulting decision. If an employer has a genuine discretion to select a proportionate response from a contractual range, the issue may be whether the employer addressed the proper purpose and relevant evidence and reached a rational result. Where the contract prescribes one deduction for each identified service failure, the issue is whether the failure occurred, how the definition applies and whether the arithmetic is correct. It would obscure the analysis to ask whether the calculated deduction was a rational exercise of discretion when the contract supplied no discretionary choice.

The precise contractual scope and grammatical form of any express reasonableness obligation also require close attention. In Mid Essex, an obligation to take all reasonable action to reduce costs did not create the different negative obligation alleged by the other party. At paragraph 147, the Court of Appeal rejected the attempt to transform the clause into a prohibition against making unreasonable claims. The judgment then relied at paragraphs 150 to 154 upon the detailed contractual scheme and context when construing the reach of general language. A broad appeal to reasonableness cannot replace identification of the act which the clause actually requires.

Construction contracts commonly contain both prescribed machinery and powers which require a genuine evaluative judgement. A payment clause may direct the contract administrator to value measured work using stated rates and quantities. Factual and interpretative disputes may arise, but the clause may still prescribe the answer once those disputes are resolved. A compensation-event clause may set a defined valuation date and require forecast cost assessed under stated components. The assessor cannot substitute a different valuation method because it appears fairer. By contrast, a power to accept an alternative security, consent to a proposed replacement or determine an interim extension "as is fair and reasonable in the circumstances" may require evaluative judgement within the bounds of the contract.

The professional or contractual label attached to the nominated decision-maker cannot settle the classification issue. An employer, project manager, engineer, architect, contract administrator, expert or arbitrator may perform different functions under different clauses. The same person might calculate a payment under fixed rates, evaluate the adequacy of submitted particulars, certify completion and exercise a power to grant an interim extension. Each individual function must therefore be classified by reference to its own contractual wording, purpose and context. General propositions about the person's role cannot override the wording and structure of the individual provision.

The source of the decision-maker's authority must also be kept separate from later review powers. A contract administrator may make an initial assessment, while an adjudicator or arbitrator may possess power to open up, revise or replace it. Later provisions may make an expert's determination final except for manifest error. Judicial review of a contractual discretion may examine whether the power was lawfully exercised without substituting the court's preferred substantive result. The available remedy depends upon the contract and dispute-resolution machinery, so a claims submission must identify both the defect and the route by which it can be corrected.

A reliable classification exercise asks four connected questions about the operation of the provision under examination. It begins by identifying the event which activates the clause and the act which the decision-maker must perform. Next, the analyst asks whether the contract prescribes the inputs and resulting answer or permits a choice among outcomes. Finally, the applicable form of contractual or legal review must be identified for that particular decision. Those questions prevent the analyst from assuming that every decision is either wholly objective or wholly discretionary. A clause may contain fixed gateways followed by an evaluative assessment: entitlement may depend upon a defined delay event, while the period of an interim extension must then be assessed as fair and reasonable.

The supporting factual and expert evidence should then be organised around that four-stage contractual structure. Fixed gateways require proof of the specified facts and compliance with procedural conditions. Any prescribed calculation requires verified inputs, correct contractual rates and transparent arithmetic which can be checked independently. Evaluative stages require a record of relevant material, uncertainties, alternative conclusions and reasons. Where one stage is not established, a persuasive analysis does not conceal the omission. It states the evidential boundary and explains the consequence which the contract gives to it.

4. Reasonableness in extension-of-time decisions

An extension-of-time decision begins with the contract, not with a preferred method of delay analysis. The decision-maker must identify the relevant event, the affected contractual obligation, any notice or particulars required, the causal question, the valuation date and whether the assessment is interim or final. Despite that evaluative expression, "fair and reasonable" does not free the decision-maker from those requirements. It describes the evaluative task permitted by the clause after its contractual conditions have been addressed.

An interim assessment is made while the project record remains incomplete and future effects may be uncertain. Its provisional character does not justify unsupported assumptions, unexplained compromise or evidential guesswork by the decision-maker. The decision should state the information available, the period assessed, the assumptions adopted, the evidence which remains outstanding and the contractual route for later review. A final assessment may use the complete record and actual progress, subject to the wording of the contract. Conflating the two stages can produce false precision in an interim decision or an unjustified refusal to reconsider the position when the final machinery requires review.

In London Underground Ltd v Citylink Telecommunications Ltd [2007] EWHC 1749 (TCC), Ramsey J considered a challenge to an arbitral award granting an interim extension of time. Clause 31.7 required an interim extension "as is fair and reasonable in the circumstances" where a delay event would prevent or delay compliance with the contractual timescale. The judge held at paragraph 164 that the remedy was not tied to one particular analysis and that its assessment necessarily contained a subjective element based upon the circumstances.

Ramsey J then explained at paragraph 165 that recognised methods of critical-delay analysis may assist the decision-maker, but do not themselves determine the fair and reasonable extension. Such analysis forms part of the expert evidence from which the contractual answer may be reached. The arbitrator had rejected critical path analysis as unsuitable for that project and derived a 48-week interim extension from primary facts, causative inference and mitigation. At paragraphs 166 to 168, the court concluded that the arbitrator remained within the pleaded case and evidence and dismissed London Underground's application under section 68 of the Arbitration Act 1996.

The decision does not permit an assessor to dispense with the required causal analysis of the claimed delay. Ramsey J's preceding reasoning was grounded in the surviving factual case and the inferences which the evidence permitted. At paragraphs 142 to 145, Ramsey J described causation in a global claim as a matter which may be established by inference from factual and expert evidence and considered whether sufficient material remained after part of the claim had failed. Between paragraphs 152 and 160, the judge traced the arbitrator's conclusion through the dates on which power should have been and was provided, the resulting delay, the effect upon the commissioning sequence and a 13-week allowance for mitigation.

The resulting legal point concerns both the selected analytical method and the sufficiency of its evidential foundation. A recognised software model or named analytical method is not a contractual answer. Its assumptions, logic and connection with the actual project must be tested. Equally, rejection of one model does not prevent a rational assessment where primary facts and permissible inferences establish the relevant delay. The decision-maker must explain why the selected material answers the contractual question and how contrary evidence was treated.

Competing analyses should be compared at the level of their assumptions rather than their labels. One analysis may use the accepted programme but fail to account for actual resequencing. Another may rely upon as-built information but choose a baseline which already contains delay. A third may isolate one event while ignoring a parallel contractor risk. The decision record should identify those differences, determine which assumptions the evidence supports, and state what effect any unresolved uncertainty has upon the period granted.

Incomplete records create an evidential problem, not an automatic rule for or against either party. The decision-maker must determine whether the material supplied establishes the facts required by the clause and must identify any conclusion which the record cannot support. If one party controls a missing record or has failed to perform an agreed recording duty, that circumstance may form part of the evidential evaluation, but it does not authorise invention of the missing contents. The decision-maker must use the evidence which exists, draw only permissible inferences and state where the record remains insufficient.

Reasonableness in this construction setting is expressed through a transparent and traceable chain of contractual reasoning. Each granted day should be capable of explanation by reference to the contractual event, affected activity or milestone, evidential finding, causal reasoning and allowance for mitigation or overlap. That does not require a false day-by-day calculation where the evidence supports only a broader period. It requires the degree of precision which the contractual task and available proof permit. An honest statement that the evidence supports an interim range may be more defensible than a precisely stated figure derived from unsupported assumptions.

5. A structured method for reasonable contractual decisions

The following method separates contractual interpretation, factual proof, evaluation and expression of the resulting decision.

This sequence is deliberately organised around the contract and the particular power which requires a decision. An analysis which begins by choosing a delay technique may never ask whether the relevant clause requires that technique. Starting instead with the desired number may lead the evaluator to use the available evidence selectively. Beginning with the power and question disciplines the later evaluation and permits a reviewer to see whether the decision-maker stayed within the bargain.

The method also exposes clauses which combine fixed gateways with later stages requiring factual or evaluative judgement. A defined delay event may operate as an objective gateway within the extension-of-time mechanism. Whether that event affected a completion obligation may then become a question of fact and causation. The period which is fair and reasonable may require evaluative judgement from the nominated contractual decision-maker. A notice requirement may impose fixed machinery which must be applied before that evaluative stage is reached. Recording each stage prevents the standards from being merged into an undefined appeal to fairness.

The stated reasons must correspond with the evidence which the decision-maker actually considered during the contractual process. A decision should not cite a programme merely because it appears in the submission if the reasoning did not use it. Nor should a later witness statement supply an explanation absent from the contemporary decision record without acknowledging that it is later evidence. The quality of the record lies in its accurate account of the process, including genuine uncertainty and limits.

6. Applied tutorial: interim extension of time

6.1 Project record

Northbank Developments Ltd engaged Meridian Build Ltd to design and construct a twelve-storey commercial building. Clause 8.5 provides that, where an Employer Delay Event will delay completion, the contract administrator shall grant an interim extension of time "as is fair and reasonable in the circumstances". The same clause permits the administrator to review that interim assessment when further information becomes available. Before the disputed event arose, the contractual completion date was fixed as 30 September 2026.

The employer was required to provide uninterrupted access to the eastern service yard by 2 February 2026. Delivery and assembly of two roof-mounted air-handling units required use of that service yard throughout the planned sequence. Access was not made available until 30 March 2026 because an existing tenant remained in occupation. Both parties accept that the resulting 56-day access restriction constitutes an Employer Delay Event under clause 8.5.

The accepted programme dated 12 January 2026 showed delivery of the units on 9 February, assembly from 10 February to 6 March, lifting on 9 March and commissioning from 16 March. It showed fifteen working days of float between commissioning and the start of integrated systems testing. Integrated systems testing and the remaining completion sequence thereafter carried no further float. The programme narrative stated that the eastern tower crane would be used for the lift.

Meridian issued notice on 5 February and submitted particulars on 10 April, seeking an interim extension of 41 calendar days. Its delay consultant moved the air-handling sequence to commence when access became available, allowed fifteen working days of float and concluded that integrated systems testing and completion moved by 41 calendar days. That analysis assumes that the eastern tower crane remained available until the revised lift.

By contrast, the employer's planner allows an interim extension of fourteen calendar days upon a different factual and programming basis. That analysis states that Meridian could have assembled the units off site and delivered them immediately before lifting. It also assumes that the mobile crane used for façade works could have completed the lift on 4 April. No quotation, lifting plan, road-closure approval or evidence of mobile-crane availability accompanies that assumption.

Site records show that Meridian asked its supplier on 12 February whether off-site assembly was possible. The supplier replied that the completed units could not be transported beneath the railway bridge on the delivery route. Its proposed alternative involved splitting each unit into larger modules, although final weatherproofing and testing would still require eight working days within the service yard. Meridian did not submit any priced proposal for adopting the supplier's alternative module-delivery arrangement.

The eastern tower crane was dismantled on 20 March in accordance with a separate recovery programme issued after the accepted programme. Nevertheless, the parties dispute the factual and contractual reason for dismantling that crane before the delayed lift occurred. Meridian says the removal mitigated contractor delay elsewhere and that a replacement crane was ordered promptly after access became available. Northbank contends that Meridian chose the removal date for its own commercial and operational convenience. Crane records establish that a replacement mobile crane was ordered on 31 March, became available on 18 April and completed the lift on 19 April.

The daily site reports covering the period from 2 February to 15 March are materially incomplete. Reports exist for Mondays, Wednesdays and Fridays, but many Tuesday and Thursday reports are missing. Contemporary progress photographs, delivery records and meeting minutes remain available for comparison with the surviving reports. Minutes dated 17 February record that internal ductwork and controls installation continued, but neither party has produced a reliable contemporaneous update showing whether those activities consumed the fifteen working days of float.

Integrated systems testing commenced on 11 May, twenty-eight calendar days later than the accepted programme date. The contractor's updated analysis attributes the whole movement to the admitted restriction upon access to the service yard. Northbank instead contends that late controls software caused at least ten days of the movement. Emails show unresolved software comments between 6 and 14 April, but the parties have not supplied a logic-linked analysis demonstrating whether those comments affected the start of integrated testing.

The contract administrator must issue an interim decision on 20 May using the material then available. Further information may be requested, but the contract requires a decision by that date and permits later review.

6.2 Assignment

Prepare a reasoned decision path for the contract administrator which addresses the contractual power and complete evidential record. The written submission must satisfy each of the following stated analytical and evidential requirements:

1. identify the exact contractual power, trigger and deadline;
2. classify each stage as objective, fixed, discretionary or mixed;
3. state which facts are established, disputed, assumed or presently unknown;
4. compare the contractor's 41-day analysis and the employer's 14-day analysis;
5. address access, float, off-site assembly, crane availability, software delay and missing records;
6. identify any enquiry which should be completed before 20 May;
7. determine the interim extension which the available evidence supports;
8. state why the decision is fair and reasonable under clause 8.5;
9. record what remains open for later review; and
10. avoid determining any issue which the evidence does not permit the administrator to resolve.

6.3 Learner decision schedule

7. Tutor's commentary

Because the 56-day service-yard restriction is admitted as an Employer Delay Event, the contractual trigger is satisfied. The admitted duration of that event does not establish an extension of the same duration. Clause 8.5 requires an interim period which is fair and reasonable in the circumstances, so the administrator must determine the effect of the event upon the completion obligation while preserving unresolved matters for later review.

The provision contains fixed contractual machinery followed by factual, causal and evaluative stages of decision-making. Identification of the Employer Delay Event and the decision deadline are governed by the express machinery. Establishing the effect of the access restriction requires separate factual and causal findings. Selection of an interim extension from the period supported by those findings then involves evaluative judgement. Accordingly, the administrator must not treat the 41-day or 14-day figure as binding merely because it was produced by a planner.

Northbank's complete off-site assembly assumption conflicts directly with the supplier's evidence concerning the railway bridge. By contrast, the split-module proposal remains relevant because it could have reduced yard activity, although eight working days would still have been required in the yard. Absence of a price does not prove that the option was unavailable, yet the administrator cannot assume immediate adoption without information about design, procurement, transport and approval.

Meridian's 41-day analysis depends upon continued availability of the eastern tower crane, although that crane was removed before access became available. Responsibility for removing that crane remains disputed upon the present documentary record. Before deciding the point, the administrator should request the recovery programme, crane instruction and correspondence concerning dismantling. If those records cannot be obtained before the deadline, the interim decision should not make a final allocation of responsibility. Proven replacement-crane dates can still be used while reserving adjustment if later evidence shows avoidable contractor delay.

The accepted programme proves that fifteen working days of float existed in the January logic. It does not establish how much remained when the delay took effect. Materially incomplete daily reports weaken the categorical position advanced by each party concerning float consumption. Accordingly, the administrator should compare meeting minutes, photographs, delivery records and the controls-installation record. Unless that material permits a firmer finding, the interim decision must state the assumption adopted and why it falls within the available evidential range.

No software delay should be deducted merely because comments remained open between 6 and 14 April. Northbank must establish that those comments delayed the relevant integrated-testing start rather than affecting work which was already delayed by the air-handling sequence or had available float. Those emails justify further enquiry, but without logic or factual evidence connecting them to the completion movement, a ten-day deduction would be unsupported.

A defensible interim conclusion upon the stated record is an extension of twenty-eight calendar days, matching the proven movement in the start of integrated systems testing, subject to later review. This interim conclusion does not accept the contractor's delay model or its underlying assumptions in their entirety. The reasoning uses the actual lift on 19 April and the proven testing start on 11 May, rejects the employer's unsupported immediate mobile-crane assumption, and declines to deduct the alleged software period without causal proof. It avoids granting the full 41 days where the record does not establish the contractor's crane assumption or continuing effect upon completion.

The resulting twenty-eight-day extension remains provisional and subject to the express later-review mechanism contained in clause 8.5. Any later review should address responsibility for crane removal, the availability and effect of split-module delivery, actual float consumption, any critical software delay and the relationship between the testing movement and final completion. Meanwhile, the interim decision should record every enquiry made and identify the requested documents which were not supplied. This treatment reflects the process and evidential discipline identified in Braganza, while applying the construction-specific recognition in Citylink that a fair and reasonable interim extension is not dictated by one analytical method.

8. Tutorial questions

1. What contractual event activates clause 8.5?
2. Why does the admitted 56-day access restriction not establish a 56-day extension?
3. Which parts of clause 8.5 involve fixed machinery, and which require evaluative judgement?
4. Why should neither planning analysis be accepted solely because it uses a recognised delay method?
5. What conclusion can properly be reached about complete off-site assembly?
6. How should the split-module option be treated?
7. Why is responsibility for removal of the eastern tower crane unresolved?
8. What use can be made of the fifteen working days of float shown in the accepted programme?
9. Why does the software correspondence not establish a ten-day deduction?
10. How should the missing daily reports affect the interim decision?
11. Why is a twenty-eight-day interim extension defensible upon the stated record?
12. Which matters must remain open for later review?

9. Assessment standard

A competent submission must identify the contractual route, address every material issue and explain the evidential basis of the conclusion. Higher marks require a clear distinction between fixed machinery and evaluative judgement, exposure of the assumptions within each delay analysis, avoidance of unsupported findings and preservation of the proper scope of later review.

10. Authorities

1. Braganza v BP Shipping Ltd [2015] UKSC 17, particularly paragraphs 17 to 36, 51 to 64 and 100 to 105.
2. Socimer International Bank Ltd v Standard Bank London Ltd [2008] EWCA Civ 116, particularly paragraphs 60 to 67 and 146 to 158.
3. Mid Essex Hospital Services NHS Trust v Compass Group UK and Ireland Ltd [2013] EWCA Civ 200, particularly paragraphs 132 to 154.
4. London Underground Ltd v Citylink Telecommunications Ltd [2007] EWHC 1749 (TCC), particularly paragraphs 141 to 171.
5. Jones v Birmingham City Council [2023] UKSC 27, particularly paragraph 51, sub-paragraphs (1) to (3).

11. Suggested answers to the tutorial questions

These answers indicate the reasoning expected from the project record and authorities. They are not prescribed wording, and a different interim conclusion requires a stated evidential and contractual basis.

11.1 Contractual event activating clause 8.5

Failure to provide uninterrupted access to the eastern service yard from 2 February until 30 March is an admitted Employer Delay Event. The administrator must therefore assess whether and to what extent that event delayed the completion obligation.

11.2 Difference between event duration and extension

Although the access event lasted 56 days, that period does not measure its proven effect upon contractual completion. Any extension depends upon causation, available float, resequencing, mitigation, crane availability, other delay and the contractual requirement for a fair and reasonable interim assessment.

11.3 Classification of the clause

Express machinery identifies the decision-maker, decision deadline, admitted Employer Delay Event and power of later review. Findings concerning the effect of restricted access require separate factual and causal analysis of the available evidence. Selection of the interim period supported by those findings involves evaluative judgement under the words "fair and reasonable in the circumstances".

11.4 Status of the planning analyses

Neither planning analysis supplies the contractual answer automatically, although each constitutes expert evidence which may assist the administrator. Meridian's analysis assumes that the eastern tower crane would have remained available until the revised lift occurred. Northbank's analysis assumes complete off-site assembly and immediate mobile-crane availability without the supporting transport, lifting or availability records. Every material assumption must be tested against the complete project evidence before either analysis is adopted.

11.5 Complete off-site assembly

According to the supplier's 12 February response, complete units could not pass beneath the railway bridge on the delivery route. Northbank's assumption of complete off-site assembly should therefore be rejected upon the present record.

11.6 Split-module option

Split-module delivery remains a possible mitigating measure, but eight working days of final weatherproofing and testing would still have been required in the yard. Its timing, cost, design development and approval implications are not established by the present project record. Further particulars should be requested before the administrator assumes that this alternative would have removed the delay.

11.7 Removal of the eastern tower crane

Although the crane was dismantled on 20 March, the parties give materially different reasons for that decision. Nothing in the supplied record determines whether removal was reasonable mitigation of another delay or a contractor choice which increased the consequences of restricted access. Before responsibility can be allocated, the recovery programme, instructions and relevant correspondence must be obtained and examined.

11.8 Treatment of float

Fifteen working days of float appear between commissioning and integrated testing in the accepted programme. Incomplete progress records do not establish how much remained when access became available. The administrator may use the accepted programme as the starting point, but must state any interim assumption and reserve the matter for review against fuller records.

11.9 Software correspondence

Open comments between 6 and 14 April do not prove that software delayed the start of integrated testing. The employer has not supplied a logic-linked or factual analysis connecting those comments to the testing movement. Further enquiry is justified, but the present evidence does not establish the employer's proposed ten-day deduction.

11.10 Effect of missing daily reports

Missing reports reduce the certainty with which progress and float consumption can be established during the affected period. Their absence does not permit the decision-maker to assume that either party's factual position is correct. The administrator should use the surviving reports, minutes, photographs and delivery records, identify the remaining gap and limit the interim finding to what that evidence supports.

11.11 Defensible interim extension

An interim extension of twenty-eight calendar days is defensible because it corresponds with the proven movement in the start of integrated systems testing, uses the actual replacement-crane and lift dates, rejects unsupported employer assumptions and avoids accepting the contractor's unproven 41-day model. The administrator must state that the figure is provisional rather than a final determination of every cause.

11.12 Matters reserved for later review

Later review should address responsibility for crane removal, the practical effect of split-module delivery, actual consumption of float, any proven critical software delay and the connection between the testing movement and final completion. The decision should identify the requested documents and explain that the reservation arises from evidential limits, not from unwillingness to decide.

Scope of the lesson

This lesson states principles of English contract law and applies them to a fictional construction project. It does not determine the effect of any particular standard form, bespoke amendment or live project record. The complete executed contract, governing law, dispute-resolution provisions and evidence must be examined before advice is given or a decision is challenged.