I’m not sure about the law on this – I’m sure some of our members can quote chapter and verse – but I would have thought a mechanism does exist, firstly to advise a customer (in writing, obviously) that their vehicle is in an extremely dangerous condition and not safe to be driven on the public roads, and secondly to advise that if they do choose to drive the vehicle away you are duty (and probably morally) bound to inform the local plod. That’s not going to endear you to your customer, but it might save a life.
Clearly that wouldn’t be appropriate in the case of a brake that was just pulling, but a burst brake pipe?
Does anyone know the law on this?