You have a Duty of Disclosure under The Consumer Insurance (Disclosure and Representations) Act 2012.

You must take reasonable care not to make a misrepresentation to the insurer, under the Consumer Insurance (Disclosure and Representation) Act 2012. This means that all the answers you give and statements you make as part of your insurance application, including at renewal and when an amendment to your policy is required, should be honest and accurate. If you deliberately or carelessly misinform the insurers, this could result in part or all of a claim not being paid.