When 'Best' Is Not Enough: Drafting Endeavours Clauses for Tougher Trading Conditions

Endeavours clauses are among the most negotiated and least understood provisions in English commercial contracts. They promise effort rather than outcome, yet businesses often draft them as if a court will later supply the missing detail. In 2026, with margins under pressure and supply chains still prone to disruption, that approach is increasingly risky. A clause that reads comfortably in a board paper may prove difficult to enforce, or expensive to defend, when a supplier misses a launch date or an earn-out target slips.

Three formulations, not a simple ladder

Courts in England and Wales interpret endeavours clauses objectively, in context. There is no statutory hierarchy. 'Reasonable endeavours' generally requires a party to take one reasonable course of action; it does not require every conceivable step. 'Best endeavours' imposes a higher standard and may require a party to act against its immediate commercial interest, though not to the point of ruin. 'All reasonable endeavours' sits uneasily between the two: it may require more than a single reasonable route, but it is not a guarantee.

Case law illustrates the point. In Rhodia International Holdings v Huntsman International, 'reasonable endeavours' meant that a party could choose between reasonable options rather than pursue every possible route. In Jet2 v Blackpool Airport, 'best endeavours' required practical steps to keep an airport operating, even where those steps carried cost. The lesson is not that one phrase is always stronger. It is that the obligation must be read against the objective, the parties' expectations and the commercial background.

Tighter conditions expose vague targets

When trading conditions tighten, endeavours clauses move from boilerplate to battleground. A supplier covenant to use 'best endeavours' to maintain service levels may be tested during a capacity crunch. An M&A condition requiring 'all reasonable endeavours' to obtain regulatory approval may become the difference between completion and a broken deal. A joint venture obligation to use 'reasonable endeavours' to secure planning permission may conceal disagreement about how much litigation or community consultation is required.

Courts will not rewrite a bargain to make it work. If the target is too vague, or the steps are wholly within a third party's control, the clause may be unenforceable for uncertainty. Even where it is enforceable, the remedy may be damages that are hard to quantify. The practical question is therefore not simply which label to use, but what conduct the parties genuinely expect and how that conduct can be measured.

A drafting checklist

Start with the objective. Specify what success looks like: a date, a regulatory milestone, a service level, a revenue target or a defined approval. Avoid formulas such as 'use best endeavours to progress the project' without identifying the project, the timetable and the decision-maker.

Choose the standard deliberately. Do not assume that 'best' is always appropriate. A high standard may be commercially unacceptable to a supplier and may invite disputes about cost. If the parties intend a hierarchy, say so expressly and define what each tier requires.

Address money. State whether the obliged party must incur expenditure, and if so, whether there is a cap. Clarify whether it must forego revenue, accept liability, commence litigation or provide security. A court may infer some of this from context, but inference is a poor substitute for agreement.

Identify constraints. Carve out matters requiring third-party consent, regulatory approval or board sanction. Use objective qualifications where possible. 'Commercially reasonable' is not self-defining; consider a definition tied to measurable criteria.

Create governance. Require written reports, joint steering meetings, decision logs and escalation. These mechanisms do not merely improve delivery; they generate the evidence that will matter if relations break down.

Consider remedies. Service credits, step-in rights, termination triggers and cure periods can be more useful than a broad endeavours promise. Draft them as enforceable contractual mechanisms, not penalties.

For M&A, distinguish between efforts to obtain approval and efforts to satisfy conditions. Consider who controls the application, what information is shared and whether a reverse indemnity or break fee is appropriate. For supplier contracts, link efforts to service levels, business continuity and exit assistance.

Evidencing effort when a dispute lands

Disputes about endeavours clauses are often disputes about records. A party that says it did everything reasonable must show what it considered, when, at what cost and why it chose one route over another. Contemporaneous documents are decisive: board minutes, risk registers, option papers, cost estimates, correspondence with regulators and third parties, resource allocation records and internal escalation notes. Witness evidence can fill gaps, but memories fade and litigation is unforgiving. Good governance should be designed before the dispute, not after.

Privilege requires care. Internal legal advice may be protected, but factual records of decisions are not automatically privileged. Parties should assume that their decision trail will be disclosed in a commercial dispute. The record should therefore demonstrate rational, documented effort rather than merely assert it.

Conclusion

Endeavours clauses are not a substitute for clear commercial deal-making. They allocate risk around uncertainty, but they work best when the objective, the standard, the cost boundaries and the evidence trail are all specified. In a year when trading conditions remain demanding, that discipline is not legal pedantry. It is the difference between an obligation a court can enforce and a sentence that only looks like one.