Insuring a borrowed car

lisyloo

doesnt fully comp insurance on your own car, enable you to drive insured on someone elses?

SOME policies do (not all).
It used to be universal but you ahve to be careful now because some companies have withdrawn it.

It's called DOC (driving other cars).
The problem with it is that it is 3rd party only.
Some people lending out their cars would not be happy with this and would want it insured full comp.
I hve lent my car out on this basis before but it was 19 years old when I scrapped it, so I accepted the risk. A lot of people with a decent car want it properly insured if they are lending it out.