It may be that my information is out of date, but I am genuinely surprised. It was declared legally impossible when I tried to do it - some years ago admittedly - and that was confirmed by my lawyer colleague.
Perhaps it's changed. I would think it a legal minefield.
It's a moot point - the other contributions have given sufficiently convincing reasons for getting your own car rather than borrowing one.
Even if you can insure the car, if you do destroy it in an accident, there may be a lifelong feeling of distrust towards you from the other person. This would depend on your relationship with the person, but nobody ever wins from an insurance payout. It's generally less than what you can replace the car for, it does damage to somebody's insurance rating, it's just not fun all round.
Buy your own car and know that you don't owe anyone anything.