I've already answered this question here:
http://www.theanswerbank.co.uk/Motoring/Questi on271842.html
I'm posting here, however, to correct Hamish's post. Cars don't require insurance. Drivers do. For example, if my friend lets his insurance policy expire, I can still drive his car (because of the 'third party - any vehicle' provisions in my insurance). The fact that the policy which specifically referred to that vehicle has run out is completely irrelevant.
Chris