D&C Builders Ltd v Rees is a landmark case in English contract law. The case was heard in the House of Lords in 1965 and concerned the issue of duress and whether it could be used as a defense for non-payment of a debt.

In the case, the defendant, Mr. Rees, had commissioned the plaintiff, D&C Builders Ltd, to carry out some building work on his property. However, when the work was completed, Mr. Rees refused to pay the full amount owed, claiming that he had been put under duress by the builders.

The duress in question was that the builders had threatened to remove their equipment from the property until the outstanding balance was paid. Mr. Rees argued that this threat constituted economic duress, as he had no other option but to pay the money in order to avoid the inconvenience and expense of finding another builder to complete the work.

However, the House of Lords rejected Mr. Rees’s argument and found that the threat of removing the equipment did not constitute duress. Lord Denning stated that “the threat of breach of contract cannot be regarded as duress, since it is a lawful act.”

The case established an important precedent in English contract law, clarifying the boundaries of what constitutes duress and when it can be used as a defense. It also highlighted the importance of clear and unambiguous contractual terms in avoiding disputes between parties.