To begin with our son had his own insurance on his own car that covered him to drive other cars not belonging to him as long as they were insured by their owners. However, as time went by, he received phone calls from insurers egging him to switch. He would switch on a like-for-like basis if it was cheaper. He has done this since he passed his test at 17 and he is now 22. Recently, he was driving my car with permission when he was stopped by the police. They checked his insurance by calling his insurance company who said he was no longer covered to drive other cars not belonging to him until he is 25. This rule had been changed from the original in the small print of his policy. He was fined £250 with penalty points.