In Britain a car that a policeman believes is being driven by someone not insured to drive it can be confiscated and crushed, and a policeman can check with the "Motor Insurers Database" (MID)to find out who is insured for that particular vehicle.
Trouble is that the MID is not always 100% up to date, as I found out one day when using a friend's car. I had been listed on her policy for about four years, but that had not yed got recorded on the MID. Fortunately when the cop accused me of driving unisured we were only about 400 yards from my friend's house and it was possible to take the cop there so that he could see her insurance certificate (with my name listed on it). If all this had happened further away her car might have been crushed!
More recently, the authorities have decided to allow the public access to the MID "so that one can check that one is insured", but the site (www.askmid.com) only allows one to check that there is insurance on the car, not who is covered by said insurance (so it does not help if you are about to drive a car someone else lends you)
The body responsible for all this is the MIB (Motor Insurers Bureay, I think) and I wrote to them pointing out the above defect. Here is their answer (copied+pasted):
Thank you for your e-mail, sorry for the delay in responding.
Please find attached our response to your query.
Customer Service Manager
Is your car at risk of being seized by the police? Put your mind at rest now......www.askmid.com