Written notice by an insurer of intent to cancel insurance, or written notice by an insured requesting cancellation.

Usually proportional treaties are for an unlimited period, i.e. they continue for as long as both parties agree to maintain the contracts in force. However, either party may decide to cancel the treaty and this must be done at a specified date (for example, the anniversary date of 31st December for treaties incepting at 1st January) by giving notice to the other party of its intention to cancel, usually 3 months in advance.

A regulated consumer credit agreement may be cancellable under the Consumer Credit Act 1974 where negotiation before the transaction took place face to face with the customer and the agreement is signed by the customer off trade premises. Special cancellation notices must be provided and the customer has a short period after the agreement has been signed (a "cooling off" period) of five days (or fourteen days where the goods are ordered by mail order) to change his mind and cancel the order.