He was either wrong, or lying to you.
It is only cat A cars that have to be crushed, and normaly there is not much left of them.
To be Cat A, it is probably already broken in half or had the roof cut off or similar.
Cat B is not allowed to be repaired or used on the road again, but can be broken for parts. If you want to retain it, you have to give a written undertaking to the authorities that it will never again be used on the road. (so you can still use it on the track, if a sports car, or off road if a 4X4), but they really dont like letting you keep it unless you can demonstrate a reasonable reason, i.e. using most of the parts on another car etc as traditionaly it is cat Bs that have been dangerously "cut & shut"
Cat C is a pretty bad accident, but you are allowed to repair it.
Cat D is a minor accident, and only written off because it was not worth much.
Cat F is fire. I once heard that Cat F's have to be crushed, but I dont think that is correct. However, unless a car fire is put out with in seconds of it starting (in which case it wont be written off anyway), then there is not normaly anything left other than a burnt out shell.
