No: a formal contract is not legally required for partnering, but partnering does not change the law of contract, so a collaborative relationship without agreed enforceable terms leaves the parties exposed, and the practical course is to use a standard partnering form

No, a formal contract is not legally required for a partnering project, but doing without one is a real risk. Partnering is a way of working; it does not change the law of contract. If a dispute reaches a court, the court still asks whether the parties intended legal relations and agreed terms certain enough to enforce, and a long or friendly relationship does not answer those questions. A supplier that had dealt with a retailer for thirty years could not imply a contract or a notice period from the relationship, because the terms were too uncertain and estoppel cannot found a cause of action. In construction, partnering negotiations have been held not to define the parties' obligations, and starting work under a partnering ethos without a formal contract has left the applicable terms to be settled by the court. The parties should select and execute terms suited to their arrangement, then operate the partnering relationship within that contractual framework.