Another problem landing on a motorway is that a multi-car pile up results, with possible multiple deaths and injuries. Maybe only a small risk, but I have no doubt that if it did happen the pilot would be prosecuted.. .. .The CAA would present a very simple case - there were lots of suitable fields around which you'd been trained to land in. In most parts of the UK they'd be able to find at least a few within gliding distance. These may have ripped the landing gear off, but that's much better than the carnage that was caused. If there weren't any suitable landing places then this was a built-up area and you should have been flying at a height from which you could glide clear. Indeed they may even define the motorway as a built up area.. .. .The pile-up may not even directly be your fault, but that's not the way the press will paint it. It would be quite hard to present a strong defence, except for a forced landing at night.. .. .Pessimistic maybe, but I think I'd rather write the plane off in a boggy field and let the insurance company pay so long as I though my passengers and I were going to walk away.