Can you take advantage of your opponent’s mistake?

In the course of a litigation it is rare that a solicitor will make a fundamental mistake that resolves the case in favour of his opponent. However when this rare situation does occur, as it did in Wills v Strategic Procurement (UK) Ltd, it raises an interesting question of how the opponent should react.

18 February 2013

In the course of a litigation it is rare that a solicitor will make a fundamental mistake that resolves the case in favour of his opponent. However when this rare situation does occur, as it did in Wills v Strategic Procurement (UK) Ltd, it raises an interesting question of how the opponent should react.

It is an essential rule of contract law that if an agreement looks like it has been validly concluded it will be assumed that the agreement is binding on the parties. The lack of intention by one party is not usually of any relevance and generally that party is barred from relying on their lack of intention. There are exceptions to this rule, such as if one party has misled the other.

In Wills v Strategic Procurement (UK) Ltd actions were raised in both Scotland and England. The parties agreed that only the English action should continue. The Scottish action was disposed of by agreement in writing but the specific wording of the agreement meant that the action was deemed to have been settled entirely. The consequence of this was that the English Court was forced to dismiss of the action before it.

It was never the intention of the pursuer's solicitor to dispose of the English action. He was just unaware of the full consequences of the agreement. The solicitor of the other side was, however, aware that the agreement would dispose of the entire action.

Mr Wills argued that his opponent took advantage of the mistake and applied to the Court to have the agreement set aside on the basis that there was no consensus. The court was asked whether the fact that the other party knew of the error, but did not cause it, was enough to discharge obligations under the contract.

It was argued for Strategic Procurement that to set aside the contract the mistake must have been induced by the other side. Just knowing that there was an error was not enough. This was rejected by the judge. The judge was clear that a bad, yet fully valid bargain can be enforced but where the mistake relates to the effect of the agreement it is possible to set the agreement aside. In the judge's view this is a fair outcome as there was no true meeting of the minds.

It was pointed out by the judge that it would have been open to Mr Wills to sue his solicitor for negligence. However the result illustrates that it is open to the mistaken party to have the contract set aside. This case means that it is not possible to set traps for your opponent. If a solicitor is aware that his opponent is in error he should tell him or risk the agreement being declared invalid later.

Read the full case report.