“However, in the case of a car dealer, selling a demonstrator, the car will normally be sold on relatively quickly in the course of business to a customer at (usually) a higher price than the dealer bought it for. Since the dealer has already borne VAT on the amount of the purchase price he had to pay, the Commissioners took the view that it would not be appropriate for the sale by the dealer to carry VAT on the full amount of the sale price. Rather, United Kingdom law required the dealer only to account for VAT on the 'margin' between his purchase price and the sale price.”