What happens if you get something wrong on an insurance application?

It depends heavily on why it was wrong, and modern law treats an honest mistake very differently from a deliberate one.

In the UK, the Consumer Insurance (Disclosure and Representations) Act 2012 replaced a harsh older regime under which almost any inaccuracy could void a policy entirely. Consumers now have a duty to take reasonable care not to make a misrepresentation — a much fairer standard — and the consequence is graded by the insurer's assessment of your conduct.

If the misrepresentation was honest and reasonable, the insurer must pay the claim in full. Getting something genuinely ambiguous slightly wrong is not fatal.

If it was careless, the remedy is proportionate to what the insurer would have done had it known. If it would have charged more, the claim is reduced by that proportion — declare a lower mileage than reality and a £10,000 claim might settle at £8,000. If it would have refused cover altogether, the policy can be voided with premiums refunded. If it would have imposed a different term, the claim is treated as though that term had applied.

If it was deliberate or reckless, the insurer can void the policy, refuse the claim entirely, and keep the premiums. It may also be recorded on industry databases, which affects future applications, and can constitute fraud.

Common accidental errors that matter: occupation described loosely, mileage estimated optimistically, modifications not declared, additional drivers omitted, previous claims or convictions forgotten, and — very commonly — "fronting", where a parent is named as main driver on a car mainly used by a child. Fronting is treated as deliberate misrepresentation.

If you spot an error, tell the insurer promptly. Correcting it before a claim is straightforward; discovering it during one is not.