“Best Endeavours” Obligations: How Much Effort Is Required?

If you’ve ever reviewed or signed a contract, there’s a good chance you’ve seen the term “best endeavours” in the fine print. It’s a familiar phrase in UK business agreements - and one that often causes confusion. How much effort does “best endeavours” really require? Does it mean moving mountains, or just making a sensible effort? And how do you know if you’ve done enough?

If you’re drafting, negotiating, or relying on a contract that mentions “best endeavours,” it’s essential to understand what the phrase means in law. Getting it wrong could lead to a costly dispute, while getting it right can protect your business and clarify expectations from the start.

This guide explains what “best endeavours” means in UK law, how it differs from “reasonable endeavours,” how courts interpret these obligations, and what steps you can take to stay compliant and confident when using them in your contracts.

What Does “Best Endeavours” Actually Mean?

In legal terms, “endeavours” refers to the effort a party must make to achieve a specific contractual outcome. When a party agrees to use their “best endeavours,” it means they must do everything reasonably within their power to fulfil that obligation - short of acting unlawfully or destroying their business.

In practice, this is a serious and proactive obligation. A party bound by a “best endeavours” clause must take all reasonable steps that a prudent and determined businessperson would take in similar circumstances to try to achieve the result.

For example, if a contract says you must use “best endeavours” to obtain regulatory approval or third-party consent, you’ll be expected to:

• Take prompt and consistent action

• Explore alternative routes to achieve the objective

• Commit reasonable time, effort, and financial resources

• Demonstrate persistence and follow-up over time

You aren’t required to do something illegal, break other contracts, or act against your company’s core commercial interests. But you are expected to go beyond a token or minimal effort.

Key Points About “Best Endeavours”

• It is not a guarantee of success, but it demands more than a “reasonable” or “casual” attempt.

• It requires diligent, timely, and proactive effort.

• You aren’t expected to bankrupt your business, but you must act seriously and resourcefully.

• The standard depends on context - including the scale of the deal, your resources, and industry practice.

Courts have described this as an obligation “to do what can reasonably be done in the circumstances” (Sheffield District Railway Co v Great Central Railway Co ).

How Does “Best Endeavours” Differ From “Reasonable Endeavours”?

“Endeavours” clauses are often used when a contract goal depends on factors beyond one party’s full control. But the type of clause chosen affects how much effort is legally required.

In UBH (Mechanical Services) Ltd v Standard Life Assurance Co , the court held that “best endeavours” may require a party to sacrifice some commercial interest, whereas “reasonable endeavours” allows for more discretion.

In Jet2.com Ltd v Blackpool Airport Ltd , the court emphasised that the context of the agreement matters - “best endeavours” doesn’t override a party’s broader business purpose or create obligations that contradict it.

The key takeaway for businesses: “best endeavours” is a high bar, and you should only agree to it if you’re confident you can perform at that level.

When Are “Best Endeavours” Clauses Used in Business Contracts?

You’ll often see “best endeavours” language where one party can’t guarantee an outcome that depends on third parties or external approvals. Common examples include:

• Securing landlord consent when transferring a lease

• Obtaining regulatory, planning, or supplier approvals

• Delivering a project where completion depends on third-party cooperation

• Applying for licences, permits, or certifications

• Partnership or joint venture agreements where funding or approvals are required

Using “best endeavours” signals that, while absolute success isn’t promised, serious and sustained effort is.

How Do Courts Interpret “Best Endeavours” Obligations?

There is no single statutory definition of “best endeavours.” Instead, courts look at the context and facts of each case.

Judges typically consider:

• The specific outcome the clause refers to

• The steps actually taken to achieve it

• The standard practice in the relevant industry

• The party’s resources and scale

• Whether taking further steps would have involved unacceptable risk or cost

For instance, if your business agreed to use “best endeavours” to obtain a supplier licence, a court would expect to see records showing you contacted the supplier, explored alternatives, escalated the issue, and generally acted with persistence.

Failing to act because it was inconvenient or costly (but affordable) is unlikely to meet the “best endeavours” standard. However, you’re not expected to jeopardise the business itself.

Courts have repeatedly emphasised that “best endeavours” is a substantial obligation, not a token one. Documenting your actions is critical - you should be able to demonstrate your efforts if ever challenged.

How to Comply With a “Best Endeavours” Clause

If your contract includes a “best endeavours” obligation, follow these practical steps:

• Document everything - Keep a clear record of all steps, correspondence, and time spent pursuing the goal.

• Act promptly and consistently - Don’t delay or stop at the first obstacle. Show sustained commitment.

• Be resourceful - Try alternative approaches if your first plan doesn’t work.

• Balance commercial sense - Go beyond minimum effort, but avoid unreasonable risk or expense.

• Communicate openly - Keep the other party informed. Transparency supports your position.

• Get professional help - If the task involves regulatory or technical complexity, seek expert advice early.

If challenged, a detailed paper trail showing continuous, practical action will be your strongest evidence of compliance.

Negotiating and Drafting “Best Endeavours” Clauses

Because “best endeavours” can create demanding obligations, it’s important to define the limits clearly when drafting or negotiating contracts.

• Tailor the clause - Specify what actions count as fulfilling the obligation, such as applying within a set timeframe or contacting named authorities.

• Include exclusions - Make clear what you won’t be required to do (for example, incurring costs above a stated amount, or breaching other agreements).

• Avoid ambiguity - Use defined timeframes, measurable standards, and agreed limits wherever possible.

• Be realistic - Only agree to “best endeavours” if your business genuinely has the resources and control to meet that standard.

A clearly drafted clause reduces uncertainty and helps prevent disputes later on.

Risks and Common Pitfalls

Disputes often arise because one side expects more effort than the other intended to commit. The main risks include:

• Vague wording with no clear benchmarks or limits

• No documentation of efforts made

• Assuming “best endeavours” is the same as “reasonable endeavours”

• Overcommitting resources without assessing practical feasibility

Defining obligations in writing - and managing expectations upfront - is the best protection for your business.

Example: “Best Endeavours” in Practice

Imagine your business signs a technology supply agreement requiring you to use “best endeavours” to obtain a data integration approval from a third-party platform.

To meet this standard, you would need to:

• Apply promptly and follow up regularly

• Provide all supporting documentation requested

• Explore alternative solutions if the approval is delayed

• Consider bringing in external consultants if appropriate

But you wouldn’t need to breach confidentiality obligations, pay an excessive fee, or suspend other essential operations to meet the requirement.

Should You Define “Best Endeavours” in Your Contract?

Yes - wherever possible. Because “best endeavours” is open to interpretation, it’s good practice to define it in your contract. You might:

• List required actions and timeframes

• Set clear limits on costs or resources

• Reference industry standards or specific approval processes

• Clarify what will not be required

Doing this helps align expectations, reduce disputes, and give both sides confidence that obligations are achievable.

Key Takeaways

• “Best endeavours” is a high standard of effort, not a guarantee of success.

• It requires you to take all reasonable steps within your power, even at some cost or inconvenience.

• It’s more demanding than “reasonable endeavours” and usually sits at the top of the “efforts” hierarchy.

• Courts assess each case by looking at context, industry norms, and documentation of actual actions.

• Always define the scope of “best endeavours” in writing, and seek legal advice if unsure.

If you need help drafting, reviewing, or negotiating “best endeavours” clauses in your contracts, Sprintlaw’s expert lawyers can help. Contact us at team@sprintlaw.co.uk or call 08081347754 for a free, no-obligations chat.