You cannot drive ither vehicles not owed by you by virtue of being fully comp, that is a myth. You can only do it if it says it on your certificate, does not matter if you are fully comp or otherwise. See here for a previous discussion on the subject. Beware there is a lot of total rubbish talked about this but read my answers toward the bottom. http://www.theanswerbank.co.uk/Motoring/Questi on549308.html