My hon. Friend the Member for Buckingham (Mr. Benyon) referred to lead traps. If such traps are introduced, and if they are as effective as my hon. Friend described, will they enable the Government to reduce the lead content that is emitted to the levels that are provided in the documents that we are considering, including the emissions of petrol engines? Will the traps mean that vehicles using petrol will use more petrol? That is an important economic point. I hope that the Minister will answer those questions clearly and directly.