My sons are aged 19 and 17, have now both passed their driving tests and are in the market for their first car.

This will be a small used car, probably 6-7 years old and around £4000 in value.

My questions are:

1) Is it feasible/advisable to have the car in joint ownership between them?
2) How can I make their insurance cover (legally) the cheapest (they have never been insured before)?

Do you advocate 'telemetric black boxes' for this purpose?