Basically your insurance company will send you a certificate with all your insurance details on saying that you have a years no claims just before its due to run out. When you come to do your insurance- if you renew your insurance with the same company, then they will know that you have the no claims anyway, because you got the no claims with them. But if you go to a different company, they will ask you how much no claims you have (online or on the phone). They may also ask to see proof of your no claims, so you might have to send them the certificate from your old insurer to prove you have the no claims. Or you could do what i did when i sorted my insurance this year over the phone- i told them who i had been with before and they checked it up themselves (then phoned me a week later to say it had been checked and was ok) so i didnt need to send them anything.