As others have said, the insurance issue is key here. Here’s an extract from AA guidance on driving other cars. Why on earth have you not checked out the insurance position? Quite frankly, lending a potentially lethal weapon to someone without checking this out is an act of momentous irresponsibility. I can’t understand why you haven’t considered this - both from your own point of view and from any innocent victims your friend may plough into.
‘What's the punishment for DOC uninsured?
A driver who is involved in an accident or caught without DOC insurance, even if the car they are driving is insured by the owner, will be dealt with severely by the law. They will be heavily fined with up to 8 licence penalty points, and could be banned from driving.
What's more, the owner would also face prosecution for allowing an uninsured person to drive their car. The owner's insurer will have to meet any third party damage and injury costs but would almost certainly cancel the policy. They may then take legal action to recover their costs from the owner, who would also be liable for the cost of repairing their own car.
Insurance companies take convictions for driving without insurance very seriously. Both the owner and the driver will find it very difficult to obtain affordable car insurance in the future. This could be a very good way of losing a friend!’