In many cases, you won't need proof of your no-claims bonus. Insurance companies can check this by looking in an online database.
But, if they do ask you for proof, it can vary between insurance providers what they ask for. You may find proof on:
• Your renewal letter
• The cancellation letter you received when switching insurance companies
If you haven’t got either of these documents, you may want to contact your previous provider to get hold of them. You'll usually need to send the proof of no claims to a new provider within the first three weeks.