I cannot tell the hon. Member exactly or even roughly what volume of trade is involved, because, as he realises, this involves knowledge which we do not possess of a number of uncertainties. One does not know what the contract date is. One would not know this about goods coming into this country. One does not know when the transit began. It is not good enough to say that one can simply make the bill of lading conclusive evidence. What about goods in transit which did not come by ship? What about the time that they were loaded on to a train? What about those which came overland? There are many difficulties about transit which are not soluble in such a way as to make it absolutely certain which goods are exempt and which are not.