they have 24 hours to sort it or its lifted and impounded until its taxed or signed over but it then has added costs, if still not taxed its crushed after i think 14 days.
I work for a company that rented a yard to VINCI the company that has the deal with the government to enforce road tax.
We saw some cracking cars get crushed (Viva HB for one), brought tears to your eyes but for whatever reason they are not allowed to be sold.
The funniest was when they clamped a car which was obviously a wreck when they went back to lift the car it was absolutely rammed with rubbish..cheap skip!