Selling an old car

It is NORMAL to sell a car to a garage without a CT. They will sort out the paperwork before selling it on.

as kasseistamper notes above, if you're selling to a professional, (i.e. a garage, or a trader) then they would normally take care of that themselves.

Private sales, are usually done WITH a CT. If you make a private sale without a CT, expect to sell for significantly less.

Just make sure that if you sell it to an individual you take the rear license plate off to return to the motor vehicle office. Unless you still have it insured don't even let the buyer drive it to his home with your license plate on it.