Learning purpose

This lesson explains how a construction claimant proves disputed events, contractual compliance, causation and loss through an organised body of evidence. It examines contemporaneous project records, witness evidence, expert opinion, planned and actual programmes, logic links, progress data and the disciplined use of factual inferences.

Successful completion requires the learner to distinguish a document from the proposition which it proves; test later reconstructions against contemporaneous material; assess witness and expert evidence within their proper functions; examine native programme logic rather than accepting a plotted result; reconcile planned, recorded and actual progress; and prepare an evidence matrix which identifies both support and remaining evidential gaps.

1. The evidential architecture of a construction claim

A construction claim is proved by establishing the material propositions required by the contract and the relief claimed. The evidential exercise therefore begins with the pleaded or asserted case, rather than with the volume of documents accumulated during the project. A contractor alleging late design information may need to establish the required information, the contractual responsibility for providing it, the date when it was required, the actual date and status of issue, compliance with any notice condition, readiness to perform the affected work, the resulting effect upon completion and any resulting recoverable expenditure. Each proposition presents a separate question; a transmittal may prove the date of issue, yet it cannot by itself prove readiness, critical delay or loss.

The same discipline applies when the employer advances a defence, deduction or counterclaim. An allegation that contractor labour shortage caused delay requires evidence identifying the relevant trade, workface, period, planned resource, actual resource and resulting production effect. Where defective work allegedly caused additional cost, the employer requires proof of the defect, responsibility, remedial scope, reasonable expenditure and contractual entitlement to recover that expenditure. Evidence should therefore be organised by proposition and consequence; a chronological narrative may explain the project history, but chronology alone does not demonstrate which facts satisfy the contract or establish the remedy sought.

An evidence matrix provides the necessary structure; each row should identify the proposition requiring proof, the party bearing the legal burden, the governing contractual or legal requirement, the documents relied upon, contrary material, witness evidence, any expert issue and the present conclusion. Separate rows should address event occurrence, procedural compliance, factual effect, contractual causation, duration, valuation and recoverability. Missing material should also appear within the matrix; a claims specialist who records the absence of native programme files, labour allocation sheets or cost-code detail can seek that material before the claim hardens into an unsupported position.

The matrix must also distinguish existence, authenticity, meaning and probative force; a document may exist without being authentic, while an authentic document may say little about the disputed proposition. A daily report recording twenty electricians on site does not show where those electricians worked or whether the claimed workface was available. By comparison, a progress photograph may establish physical conditions at a particular time, although its evidential force depends upon location, date, orientation and continuity. Meeting minutes may record what participants stated without proving the truth of every recorded assertion. Evidential analysis requires a reasoned account of what each item establishes and what it leaves unresolved.

Evidence should also be tested across independent record families; a drawing register can be compared with transmittals and receipt acknowledgements. Daily reports can be checked against photographs, access permits, inspection requests and delivery records. Labour returns can be compared with payroll, turnstile data and trade allocation sheets. Programme status dates can be tested against measured quantities and contemporaneous progress narratives. Agreement across records created for different operational purposes may support a factual inference, while unexplained conflict may expose unreliable data, inconsistent status practices or later reconstruction.

No evidential hierarchy makes every contemporaneous document conclusive or every later document worthless. Contemporary material often carries considerable weight because it was created near the event and before the dispute matured. Nevertheless, such records may be incomplete, copied forward, prepared for another purpose or influenced by a participant's commercial position. Later analysis may assist by reconciling records and explaining technical consequences, provided that its assumptions remain visible and testable. The proper question concerns reliability for the particular proposition, not whether the document falls within a preferred category.

A connected chain must be proved rather than a collection of isolated facts. Proof that an instruction was issued late establishes an event, but completion delay requires evidence connecting that event with affected work and the contractual completion date. Similarly, proof that personnel remained on site during an extended period establishes attendance, but recoverable prolongation cost requires evidence connecting the claimed expenditure with the compensable period and excluding unrelated cost. Every evidential link should therefore answer a defined proposition and withstand comparison with the complete project record.

The final submission should expose uncertainty rather than conceal it; where the available material proves late issue but leaves readiness unresolved, the claim should say so and identify the evidence required. Where records support some activity delay but do not establish movement of contractual completion, the analysis should stop at the supported conclusion. That approach protects credibility and permits the decision-maker to distinguish established facts from assumptions requiring further proof. A larger claim assembled from untested propositions remains weaker than a narrower claim supported through a complete evidential chain.

2. Contemporaneous records and documentary reliability

Contemporaneous records are project documents created during or near the events which they describe. They include programmes, progress updates, daily reports, photographs, correspondence, design registers, requests for information, instructions, meeting minutes, inspection records, delivery documents, labour returns, plant records and cost ledgers. Their evidential attraction lies in proximity and operational purpose; they may record what participants did before litigation required them to construct a forensic account, but neither proximity nor routine creation guarantees accuracy.

Reliability begins with provenance; the analyst should establish who created the record, when it was created, which system retained it, whether it was amended, who received it and what process governed approval or correction. A printed programme without its native file may conceal calendars, constraints, progress overrides and altered logic. Likewise, a spreadsheet exported after the dispute may no longer reveal formulas or source data. Photographs lacking metadata or a location plan may be genuine yet incapable of establishing the alleged workface condition. Provenance permits the decision-maker to understand how the record came into existence and whether later alteration can be detected.

Purpose affects meaning because project records often answer operational questions narrower than the dispute. A daily allocation sheet may record the number of operatives assigned at the morning briefing, rather than the number who remained productive throughout the shift. An inspection request may show that work was offered for inspection, rather than that every predecessor and approval condition had been satisfied. A payment application may state quantities for valuation without proving the precise date when physical installation occurred. The analyst must understand the record's function before treating its entries as direct proof of another proposition.

Completeness requires both internal and external testing; internal testing examines missing dates, unexplained revisions, copied text, inconsistent activity identifiers and entries which conflict within the same record family. External testing compares the document against other independent material; if a programme update records ductwork completion on 14 June while daily reports show continuing duct installation until 24 June, the conflict requires investigation. Either status practice, activity definition or one record may explain the difference. The analyst should not select the preferred date merely because it supports the instructed case.

Digital evidence requires preservation of its native characteristics; programme files, document-management audit trails, email headers, photographic metadata and spreadsheet formulas may disclose information absent from printed copies. Native programme files permit examination of logic links, constraints, calendars, progress overrides, data dates and revision histories. Document-control audit trails may distinguish first issue, superseded issue, later upload and formal acceptance. Preservation also requires a clear record of extraction and handling so that another analyst can reproduce the review without relying upon an unexplained working copy.

The treatment of project records in Great Eastern Hotel Co Ltd v John Laing Construction Ltd [2005] EWHC 181 (TCC) illustrates this discipline. At paragraphs 65 to 70, HHJ David Wilcox compared delay experts whose methods and research differed. The expert whose work drew upon contemporary primary documents, computer records and timed site photographs was treated as independent and objective, while the competing analysis lacked equivalent investigation. At paragraphs 117 and 127 to 128, contemporary documents and photographs contradicted recollection, and the court criticised an expert who failed to use that material.

The judgment does not establish that every photograph prevails over every witness or that one named delay method governs all claims. Its evidential force lies in the court's examination of research, objectivity and compatibility with the actual record. At paragraphs 183 to 185, the court preferred analysis which considered actual events and rejected an incomplete impacted-as-planned exercise based upon a superseded original programme. Paragraphs 209 to 223 then examine the electronic programme and altered logic links within the court's treatment of reporting and programme manipulation. Those findings depended upon the extensive evidence in that case and should remain tied to their factual setting.

Documentary weight also depends upon the proposition for which a record is used. At paragraphs 241 to 246 of Great Eastern Hotel, the court addressed construction manager's instructions within the procedural and evidential circumstances of a very large trial. The records could provide evidence that described work had been instructed or carried out, but questions of value and causal attribution remained. Accordingly, a project document may establish occurrence without establishing contractual responsibility, causation, duration or quantum.

Claims specialists should record a reliability assessment beside each document family; the assessment should identify provenance, purpose, completeness, internal consistency, external consistency, native availability and any unresolved conflict. Where a later as-built programme disagrees with daily reports, the conflict must appear within the evidence matrix and workshop schedule. A submission which silently adopts the later programme converts an assumption into an apparent fact and prevents the decision-maker from seeing the actual evidential dispute.

3. Witness evidence, memory and factual inference

Witness evidence explains events which documents record incompletely and working practices which documents assume. A project manager may explain how progress percentages were gathered, while a planner may explain whether logic changes were approved or merely entered for reporting. Meanwhile, a supervisor may identify the location shown in a photograph and the work which remained unavailable. Such evidence can be necessary, but its value depends upon personal involvement, opportunity to observe, temporal proximity, consistency and candour concerning the limits of recollection.

The first task is to separate personal observation from reconstruction; a witness may remember attending a meeting without independently remembering every matter recorded in the minutes. Another witness may describe a sequence derived from later review of records rather than continuous personal recollection. Both forms of evidence may assist if their basis is stated accurately. Difficulty arises when reconstruction is presented as memory, because the decision-maker cannot identify whether the evidence adds an independent observation or merely repeats the document selected during preparation.

Witness preparation should therefore map each factual proposition to the witness's actual involvement. The statement should identify the witness's role, relevant period, workface access, reporting responsibility and documents used to refresh recollection. It should distinguish observed facts, ordinary working practice, present recollection and conclusions drawn from records. Where the witness did not create a disputed programme or daily report, the statement should not imply knowledge of its compilation. If another participant made the relevant decision, absence of evidence from that participant should be recorded rather than replaced by second-hand assertion.

Consistency with contemporary material requires explanation rather than automatic rejection; a witness may credibly explain why a daily report used a broad activity label or why a programme status date represented substantial rather than absolute completion. Conversely, a later statement that no access existed may conflict materially with permits, photographs and daily reports recording partial work. The witness should confront that conflict directly, identify any distinction in area or time and explain the source of the present account. Silence about a contrary record weakens the evidential value of the statement.

Great Eastern Hotel provides a fact-specific example of this comparison; at paragraph 117, the court regarded one witness's recollection as unreliable where contemporary documents and photographs contradicted it. At paragraphs 127 and 128, the court attached little weight to expert analysis which did not engage with that contrary evidence. The proper proposition is therefore limited: within that trial, tested project records and photographs displaced recollection and exposed deficient expert treatment. Nothing within the judgment abolishes oral evidence or creates an inflexible documentary presumption.

Factual inference permits a decision-maker to derive a conclusion from proved primary facts. Several independent records may support an inference that an unavailable drawing prevented planned installation even though no single document states the complete causal conclusion. The reasoning must identify the primary facts, the proposed inference and realistic competing explanations. A drawing register, contemporaneous hold entry, material receipt, completed predecessor inspection and workface photograph may collectively support readiness and prevention. If labour allocation sheets show no suitable crew, the inference requires reconsideration or limitation.

An inference cannot repair an evidential void merely because the asserted conclusion appears commercially plausible. Chronology alone does not establish causation, and repeated statements of the same assertion do not create independent corroboration. Ten reports derived from one unverified planner's entry may still represent one source. The analyst must identify independence, check whether the records share a common data origin and avoid counting duplicated information as cumulative proof. Where alternative causes remain possible, the analysis should explain why the proved facts make the selected conclusion more probable.

Adverse or absent evidence must be treated carefully; missing daily records may weaken a case where the claimant controlled and ordinarily produced those records, but absence does not automatically prove the opponent's account. The decision-maker must consider whether the record should have existed, who controlled it, what steps were taken to obtain it and whether other material supplies the missing proposition. Claims specialists should identify the gap, seek disclosure and frame any requested inference by reference to the particular circumstances rather than treating non-production as automatic liability.

Witness evidence should culminate in a source schedule linking each statement paragraph to the relevant proposition and project records. That schedule reveals unsupported opinions, duplicated testimony and gaps in personal knowledge before cross-examination. It also permits the claims team to distinguish a witness who proves primary fact from a witness who explains process. The resulting account remains useful only if it assists the decision-maker to understand the evidence without asking the witness to decide contractual entitlement or technical questions outside personal competence.

4. Expert opinion and the tribunal's continuing function

Expert evidence assists with matters requiring specialised knowledge or experience, such as delay analysis, engineering causation, defects or forensic accounting. The expert may organise technical material, explain accepted methods, test assumptions and express an opinion within the instructed discipline. However, the expert does not determine disputed legal entitlement, choose the facts without evidential foundation or replace the tribunal's evaluation. Expert opinion remains evidence which must be tested against instructions, sources, methodology, reasoning and the complete factual record.

The Supreme Court examined the use of skilled evidence in Kennedy v Cordia (Services) LLP [2016] UKSC 6. At paragraphs 38 to 45, Lords Reed and Hodge addressed the admissibility of skilled evidence and set out the four considerations which govern it. The court explained that skilled witnesses may give opinion and factual evidence within their expertise, while the evidence must assist the court and rest upon appropriate knowledge or experience. At paragraph 45, the judgment preserved the court's responsibility to decide whether expert help is required rather than permitting opinion to supplant judicial assessment.

The expert's qualifications must correspond with the opinion actually expressed; general planning experience does not automatically establish competence to analyse a particular scheduling system, engineering process or cost model. Consequently, the report should state qualifications, project experience, software competence and any limits. At paragraphs 41 and 42 of Kennedy, the Supreme Court explained that skilled evidence may draw upon the work and knowledge of others, but the witness must identify qualifications and information sources. Anecdotal material should not acquire the status of expertise merely through repetition within an expert report.

Independence concerns reasoning and presentation, rather than detachment from every assumption supplied by the instructing party. The expert should identify instructions, distinguish assumed facts from proved facts, address material contrary evidence and explain any change of opinion. At paragraphs 51 to 53 of Kennedy, the court addressed impartiality and the duties associated with expert evidence, including disclosure of material considered. Paragraph 53 requires an explanation where apparently relevant material has been regarded as unimportant. A delay expert who excludes daily reports contradicting programme dates must therefore explain the exclusion and its effect.

Methodology must remain reproducible; a report should identify source files, data dates, calendars, constraints, logic changes, selection criteria and analytical steps. Another competent analyst should be able to understand how the conclusion was produced and test the result against the same material. At paragraphs 55 and 56 of Kennedy, the Supreme Court addressed whether the relevant body of knowledge or experience provides a reliable foundation. In construction claims, the label attached to a delay method cannot compensate for undisclosed assumptions or unreliable input data.

The legal team controls the evidential foundation supplied to the expert; selective disclosure may produce a technically orderly opinion founded upon an incomplete record. At paragraph 57 of Kennedy, the court stated that the legal team should provide the expert with relevant material, including adverse material. The claims specialist should therefore prepare an instruction pack indexed by issue, record family and date, while identifying known gaps and conflicts. Instructions should not state disputed facts as established or direct the expert towards a required contractual conclusion.

The tribunal remains responsible for weight and ultimate findings; at paragraph 59 of Kennedy, the Supreme Court confirmed the judicial task of assessing the evidence and testing the soundness of the expert's opinion. A clear graph cannot establish a causal link absent from the underlying records, while an impressive model cannot prove that assumed activity dates are correct. The decision-maker may accept part of an expert's analysis, reject another part and reach a factual conclusion through documentary and witness evidence outside the expert's opinion.

A direct construction application of these controls appears in the court's treatment of expert delay evidence in Great Eastern Hotel. At paragraphs 65 to 70 and 183 to 185, HHJ David Wilcox compared the experts' research, objectivity and engagement with actual events. Paragraphs 104 to 111 and 127 to 128 criticise uncritical acceptance of a party's case and failure to investigate contemporary material. Those conclusions arose from the evidence and experts in that trial; they support disciplined expert practice without converting the preferred method there into a mandatory method for every dispute.

An expert evidence protocol should therefore require a statement of issues, assumptions register, source register, methodology explanation, contrary-evidence schedule, limitations section and reproducible working files. Each opinion should link to the source records and identify whether it depends upon a disputed fact. Where data cannot support a reliable conclusion, the report should state the boundary rather than supply false precision. Expert independence is demonstrated through transparent reasoning and fair engagement with the complete record, including material which weakens the instructed case.

5. Programme evidence, logic and actual progress

A programme is a model of intended or reported sequence, not an answer produced independently of evidence. Baseline programmes may record planned logic, calendars, durations and contractual milestones; periodic updates may record status, remaining durations, logic revisions and forecast completion. As-built programmes seek to describe actual progress; each may assist different propositions, but every programme requires validation against its purpose, creation date, native data and the project records from which its status was derived.

The baseline must first be tested as a reliable expression of planned execution. That examination should identify the approved or accepted revision, relevant data date, calendars, constraints, activity coding, relationships and longest path. Acceptance for monitoring does not necessarily establish that every duration or logic link reflects an agreed contractual obligation. Conversely, later dissatisfaction with the baseline does not justify silently substituting a different plan. The claim should explain the baseline's contractual status and analytical use with appropriate precision.

Updates require examination of both status and logic; actual starts, actual finishes, remaining durations and progress percentages should be reconciled against daily reports, measured work, photographs and inspection records. Logic changes may reflect legitimate resequencing, correction of modelling error or an attempt to preserve a preferred forecast. The native file and audit trail can reveal deleted relationships, imposed constraints and out-of-sequence treatment hidden within a printed bar chart. Where logic changed, the analyst should identify when, why, by whom and with what effect upon the reported critical path.

An as-built programme prepared after the dispute began occupies a different evidential position from a contemporaneous update. It may assist by assembling actual dates across many records, but the source and reasoning for each date should remain traceable. A retrospective programme which assigns precise dates unsupported by project records cannot become reliable merely because it is visually complete. Conflicts with daily reports must be logged and resolved by reference to activity definition, location, substantial completion, residual work and record provenance.

Great Eastern Hotel demonstrates why native and contemporary material matter; at paragraphs 70 and 183 to 185, the court examined limitations within agreed as-built dates and preferred analysis which addressed actual events. At paragraphs 197 and 209 to 223, electronic programme data and logic alterations formed part of the court's factual investigation. Paragraphs 306 to 310 criticise retrospective theoretical critical paths which did not adequately engage with objective evidence. These conclusions arose from the particular programme history and evidential record before HHJ David Wilcox.

Balfour Beatty Construction Ltd v London Borough of Lambeth [2002] EWHC 597 (TCC) concerned summary enforcement of an adjudicator's decision, rather than a final trial of delay entitlement. The contractor relied upon numerous alleged relevant events and an as-built presentation, but did not present a developed critical-path analysis supported by the requested event-and-effect schedule. HHJ Humphrey Lloyd QC concluded that the adjudicator reconstructed a case and method which had not been fairly exposed to Lambeth for comment. Lambeth succeeded in resisting summary enforcement because the resulting process exceeded the proper adjudicative role and offended procedural fairness.

The decision requires careful use; the judgment supports the proposition that a referring party should present manageable material connecting events, affected activities, timing and supporting documents. It also confirms that a respondent may criticise the referring party's proof without preparing a complete alternative delay analysis. The decision does not establish that one delay methodology is mandatory in every proceeding, nor does it permit a tribunal to reject any claim lacking a particular software output. Its procedural setting and the adjudicator's undisclosed reconstruction remain attached to the court's conclusion.

Logic links should be treated as hypotheses about dependency which require factual support. A finish-to-start relationship may represent genuine physical sequence, contractual access, resource strategy or an arbitrary modelling convention. The analyst should explain the dependency and test it against workface conditions. Where work occurred out of sequence, the analysis should decide whether the model needs correction, whether actual practice displaced the planned logic or whether the status was wrong. Unexplained logic manipulation can change the apparent critical path without changing what happened on site.

Progress data requires comparable definitions; percentage complete may refer to labour hours, quantities, cost or subjective assessment, and those measures can produce different results. Activity completion may mean operational use, substantial completion, inspection readiness or closure of every residual item. A delay analysis should identify the status convention and apply it consistently. If the as-built programme records completion on 14 June while daily reports show residual works continuing, the analyst must determine whether the programme used substantial completion and whether the residual work affected successors.

The final programme opinion should reconcile plan, updates and actual records within an issue-specific schedule. For each claimed event, the schedule should identify the planned affected activity, contemporaneous status, actual constraint period, logic path, competing constraints, available float, resulting milestone effect and source documents. Assumptions should be numbered and tested; a programme becomes persuasive evidence when its dates, logic and causal conclusions can be traced to reliable project material and challenged without reconstructing the analyst's method from unexplained graphics.

6. A practical evidence protocol

The first stage is to define the proposition schedule from the contract, notices and asserted relief. Record families should then be collected in native form with their audit history. The reviewer should next reconcile dates, quantities, resources and programme status across independent sources. Witnesses and experts can then be identified by reference to their actual competence or involvement with the remaining propositions. Finally, the reviewer should record conclusions, contrary evidence, assumptions and unresolved gaps without expanding the claim beyond what the evidence supports.

Each proposition should receive an evidence status of proved, provisionally supported, contradicted, unresolved or unnecessary. Those labels should refer to the present evidential assessment rather than the ultimate tribunal decision. A provisionally supported proposition may require disclosure or witness explanation; a contradicted proposition should not disappear from the schedule because it inconveniences the case. Transparent treatment allows the claim to be corrected before submission and enables advisers to distinguish legal weakness from incomplete evidence collection.

7. Construction workshop: the retrospective as-built programme

Project record

The fictional project concerns the construction of the Northmere Civic Energy Centre by Alder Construction Ltd for Northmere Borough Council under a contract requiring completion on 30 November 2025. Alder claims a forty-two calendar-day extension and GBP 1,180,000 of prolongation cost arising from late mechanical coordination information.

Learner assignment

1. Identify the separate propositions Alder must prove before the claimed extension can be determined.
2. Assess what L11-R02 proves and what remains unproved concerning the operative information period.
3. Reconcile the competing Zone B start and finish dates within L11-R03, L11-R05, L11-R06 and L11-R07.
4. Explain how partition access affects the causal analysis without assuming either party's complete account.
5. Assess the provenance, purpose and reliability of retrospective programme AB-2.
6. Identify every logic or status assumption within AB-2 which requires further proof.
7. Evaluate the planner's statement against the contemporary record and identify necessary clarification.
8. Apply the expert-evidence controls in Kennedy to the draft delay report.
9. Apply Great Eastern Hotel and Balfour Beatty v Lambeth without overstating either decision.
10. State the presently supportable conclusion concerning activity delay and completion delay.
11. Assess whether L11-R10 proves the claimed GBP 1,180,000 prolongation cost.
12. Prepare an evidence direction identifying the native files, records and witness explanations still required.

Tutor observations

The project record proves that accepted coordinated information was unavailable until 30 May, but it also records incomplete partition access until 2 June. Any presently supportable analysis should therefore separate information availability, physical access, limited setting-out, mechanical installation and completion consequence. Neither the retrospective programme nor the contemporary update should be accepted without examining native logic and source dates.

The learner should identify AB-2 as a later reconstruction requiring full validation, rather than reject it merely because it was prepared after the dispute. Its deleted relationship, unsupported activity dates, absent source register and conflict with U06 require explanation. The expert report should identify assumptions, adverse records, methodology and limitations before expressing any reliable completion opinion.

8. Common evidential errors

• A document is treated as proof of every consequence, although it establishes only one event or date.
• A retrospective programme is accepted because its graphics appear precise, despite missing native data and sources.
• Witness reconstruction is presented as personal recollection without identifying the documents used during preparation.
• An expert adopts the instructing party's programme dates without testing contemporary records or adverse material.
• Several records derived from one data source are counted as independent corroboration of the same proposition.
• Activity delay is converted into completion delay without examining logic, float and competing constraints.
• Aggregate site cost is claimed across a period without proving expenditure, causation and contractual recoverability.
• Missing material is concealed rather than recorded as an evidential gap requiring disclosure or explanation.

9. Practitioner checklist

• Define every contractual, factual, causal and valuation proposition before collecting evidence.
• Record the legal burden and governing contractual requirement beside each proposition.
• Preserve native programme files, metadata, audit histories, spreadsheets and document-control exports.
• Test provenance, purpose, completeness and consistency for every principal record family.
• Reconcile programme dates against daily reports, photographs, inspections and measured progress.
• Identify personal knowledge, refreshed recollection and reconstruction within each witness statement.
• Provide experts with adverse material and require transparent assumptions, sources and methodology.
• Test logic links against physical sequence, access, resource strategy and actual workface practice.
• Separate event occurrence, activity effect, completion consequence and monetary consequence throughout.
• State unresolved gaps expressly and limit the conclusion to propositions supported by the evidence.

10. Authorities and further reading

• Great Eastern Hotel Co Ltd v John Laing Construction Ltd [2005] EWHC 181 (TCC), especially paragraphs 65 to 70, 104 to 111, 117, 127 to 128, 183 to 185, 197, 209 to 223, 241 to 246 and 306 to 310.
• Balfour Beatty Construction Ltd v London Borough of Lambeth [2002] EWHC 597 (TCC), concerning the presentation and undisclosed reconstruction of the delay case within adjudication enforcement proceedings.
• Kennedy v Cordia (Services) LLP [2016] UKSC 6, especially paragraphs 38 to 45, 51 to 59 and 66.

11. Suggested answers to the workshop

Answer 1: propositions requiring proof

Alder must prove the contractual information event, actual issue and accepted status, compliance with any contractual procedure, readiness of Zone B, the event's factual effect, critical completion consequence and the recoverable cost resulting from that consequence. L11-R02 supports late accepted information, while L11-R01 and L11-R03 to L11-R06 raise separate questions concerning float, partition access and recovery. Great Eastern Hotel at paragraphs 241 to 246 illustrates that proof of instructed or performed work does not itself establish value or causal attribution; the contract, notices, native programmes and period-specific cost evidence remain required.

Answer 2: information event and operative period

L11-R02 proves formal instruction on 12 May, first formal issue on 28 May and accepted status on 30 May. It does not establish that productive mechanical work was otherwise ready throughout that period or that completion moved by forty-two calendar days. L11-R03 to L11-R05 record incomplete partition access until 2 June and limited setting-out before then. Alder requires the drawing status workflow, technical evidence concerning usability, native programme logic and workface readiness records before the operative information period can be determined.

Answer 3: competing actual dates

L11-R03 and L11-R05 support limited Zone B setting-out on 29 and 30 May, partition inspection on 2 June and containment from 3 June. U06 in L11-R06 records first fix from 3 until 20 June, while AB-2 in L11-R07 records 30 May until 27 June. The discrepancy requires definition of first fix, treatment of partial work and source tracing for each date. Great Eastern Hotel at paragraphs 183 to 185 supports testing analytical dates against actual events; native files, daily quantities and inspection detail remain necessary.

Answer 4: partition access and causation

Partition access is a supported competing constraint rather than a complete answer to Alder's claim. L11-R03 to L11-R05 indicate reduced drylining labour, incomplete partitions until 2 June and partial access before inspection. The analysis should determine whether DI-17 prevented any work before 30 May, whether partition conditions independently prevented installation and whether both constraints affected different parts or periods. Because the baseline dependency requires factual validation, workface plans, trade allocation, supervisor evidence and zone-specific production records should be obtained before selecting a causal sequence.

Answer 5: reliability of AB-2

AB-2 is a later reconstruction which may assist if its sources and reasoning can be reproduced. L11-R07 weakens present reliance because the programme lacks a source register, changes baseline logic and conflicts with U06 and contemporary records. Great Eastern Hotel at paragraphs 306 to 310 criticised retrospective theoretical paths which did not adequately engage with objective material. That fact-specific treatment does not invalidate every retrospective analysis; alder should provide AB-2's native file, audit history, date-source schedule, method statement and explanation for each logic change.

Answer 6: assumptions requiring proof

AB-2 assumes that 30 May represents the operative first-fix start, 27 June represents completion, the deleted partition relationship was not factually operative and DI-17 alone controlled contractual completion. It also appears to assume that baseline float did not absorb any effect and that recovery reflected within U06 can be disregarded. Each assumption must be tested against L11-R01 and L11-R03 to L11-R06; the required evidence includes native calculations, calendars, longest-path reports, progress quantities, actual logic and an explained reconciliation of forecast and final completion.

Answer 7: planner's witness evidence

The planner's statement conflicts with records showing limited setting-out before accepted drawing status, partial access on 30 May and partition approval on 2 June. L11-R08 does not explain whether the planner personally observed Zone B or reconstructed events from AB-2. Great Eastern Hotel at paragraph 117 illustrates a fact-specific rejection of recollection contradicted by contemporary documents and photographs. The planner should identify personal observations, documents used to refresh memory, the meaning of productive access and reasons for preferring AB-2 over U06.

Answer 8: expert-evidence controls

However, the draft report does not presently disclose a sufficient source base, assumptions register or explanation of contrary evidence. Kennedy at paragraphs 41 to 45 requires relevant expertise and assistance to the court, while paragraphs 51 to 59 address impartiality, source treatment, reliable methodology and judicial evaluation. The expert should receive L11-R01 to L11-R10, including adverse records, and explain the deleted logic relationship, date selection, analytical method and limitations. A revised report also requires native working files and a reproducible calculation of any completion effect.

Answer 9: proper use of the construction authorities

Great Eastern Hotel supports comparing expert research and programme analysis with actual records, particularly at paragraphs 65 to 70 and 183 to 185. It does not prescribe one compulsory delay method; Balfour Beatty v Lambeth supports presenting a manageable event-and-effect case and preserving procedural fairness where an adjudicator develops an undisclosed reconstruction. Its decision arose during summary enforcement and does not establish a universal critical-path rule. Alder must present its own supported analysis rather than expect the decision-maker to repair AB-2.

Answer 10: present time conclusion

The record presently supports late accepted information until 30 May and delayed unrestricted partition access until 2 June. It also supports some Zone B activity effect, but does not establish forty-two calendar days of completion delay. L11-R01 shows twelve working days of float, while L11-R06 forecasts a shorter completion movement after recovery. A reliable conclusion requires native programme comparison, actual logic, later progress and the contractual completion history. The supported interim position should identify limited activity constraint while reserving completion duration.

Answer 11: monetary proof

L11-R10 does not presently prove GBP 1,180,000 as recoverable loss caused by DI-17. The summary applies an average site-cost rate across the disputed forty-two days without separating actual expenditure, baseline allowance, recovery cost or unrelated delay. Great Eastern Hotel at paragraphs 241 to 246 distinguishes evidence of occurrence from value and causal attribution, while paragraphs 374 to 395 demonstrate the consequences of deficient first-hand proof within that case. Alder requires ledgers, invoices, payroll, plant records, cost codes and a causally justified compensable period.

Answer 12: evidence direction

The direction should require native baseline, U06 and AB-2 files with calendars, logic, constraints and audit reports; the source schedule for every as-built date; complete daily reports, photographs, inspections, allocation sheets and measured quantities; the document-control history for DI-17; and period-specific cost ledgers. Witness clarification should address access, date definitions and programme compilation; the expert should then revise the analysis under the controls stated in Kennedy at paragraphs 51 to 59, while reconciling every conclusion against L11-R01 to L11-R10.

12. Knowledge check

The accompanying ten-question Knowledge Check tests documentary reliability, witness evidence, expert duties, programme logic, factual inference and application of the Northmere project record.

Closing point

Construction evidence proves propositions only when its provenance, meaning and relationship with the complete record can withstand examination. A programme, witness or expert opinion assists the claim when the reasoning remains traceable and the conclusion stops where the supporting evidence stops.

Scope of the lesson

This lesson provides general professional education concerning English contract-law principles and construction-claims evidence. It does not provide legal advice upon any project, replace the governing contract, or determine how a court, tribunal, adjudicator or contract administrator would decide particular facts.