In v Blackpool Airport Limited,[1] the English Court of Appeal was faced with two questions on a “best endeavours” clause: Is it enforceable? And what does it mean?  

The Judgment

A budget airline,, and an airport operating company, BAL, had agreed to “co-operate together and use their best endeavours to promote’s low cost services from Blackpool Airport”. When BAL indicated it would no longer accept flights outside the airport’s normal opening hours, claimed for breach of contract, arguing that the “best endeavours” clause required BAL to accept flights at any time of day or night. BAL argued that the clause was too uncertain in its content to give rise to any enforceable obligations, and that in any case it did not require BAL to act contrary to its own commercial interests.  

The Court of Appeal disagreed. It held that an obligation to use best endeavours to promote another party’s business was not by its nature too uncertain to be unenforceable, even if it might be difficult in a given case to determine whether it had been fulfilled. Further, on the facts of the case, the obligation did extend to keeping the airport open for flights outside normal hours, even if that meant BAL incurring losses.  


The case represents a high-water mark for the concept of best endeavours. While a line of previous cases had held that a party agreeing to use “all reasonable endeavours” or “best endeavours” was not thereby required to sacrifice its own commercial interests,[2] here the Court held that a party was required to do just that.  

At the same time, the Court refused to define the outer limits of BAL’s duties under the clause. This refusal is understandable. “Reasonable endeavours” and “best endeavours” clauses are used in all manner of contracts in a wide range of industries and sectors. The Court will not be drawn into writing the contract for the parties; to have sought to define the content of such a clause might have set a precedent which would prove inappropriate in other cases. v BAL provides comfort that best endeavours” clauses should normally be enforceable, but highlights the risks inherent in their use. Where parties fail to specify in detail what each party must do, one may find itself held to a bargain it did not make, and both may find themselves embroiled in uncertain and costly litigation.