§ Mr. Litterickasked the Secretary of State for Transport what research his Department has commissioned to discover the connection between the efficiency of petrol engines and the tetraethyl lead content of petroleum fuel.
§ Mr. Horam:There is a well-established relationship between the lead content of petrol and the efficiency of petrol engines. Engines with high compression ratios, and therefore a high performance capacity, need high octane fuel, and this is progressively more difficult and expensive to produce when the lead content is reduced. A reduction of lead content below a certain point makes it expedient to have engines with lower compression ratios which are capable of working on lower octane fuel.