It depends on the method of towing. If an A bar is used, the towed vehicle becomes a trailer, and doesn't need tax, mot or insurance.
The the lead vehicle must be insured for towing and you have the problem of weight - if the combined weight is more than the driver is licensed to drive, he cannot use this method.
If the car is towed by rope, then the usual rules of the road apply - must be taxed, mot'd and insured - unless it is being towed to a pre-booked MOT test or to a garage to have the work necessary to pass the MOT. And the driver will have to be licensed.



