asked the Secretary of State for Trade and Industry what progress is being made in research into quieter aeroplane engines.

The results of many years of Government support for such general research, in collaboration with industry and universities, have already contributed to the quieter engines now in or approaching service such as the RB211 and the M45H. Current measures cover extensive additional research into methods for reducing aero-engine noise. These include Government contributions towards the costs of two major programmes in industry: one aimed at demonstrating the possibility of further reductions in noise levels of the RB211 and the other at demonstrating the practicability of developing an ultra-quiet engine based on the M45.

I thank my hon. Friend for that answer. May I take it as a categorical refutation of the canard that Her Majesty's Government are deliberately retarding research into quieter jets? Can my hon. Friend say why it is not yet compulsory to fit silencers to light aircraft engines?

It is simply not true that the Government are retarding research into quieter engines. We are in the forefront of world pioneering in this respect, and the RB211 has already cost the British taxpayer more than £190 million. A substantial number of the engines used in light aircraft are not manufactured in this country.

Will the Minister now honour the obligation he assumed in the House on 22nd October when, in answer to a question from this side, he said—column 679 of HANSARD—that the Government were spending substantial sums on research and development to quieten engines but because he could not then give details he would write to me? Why has he not fulfilled that obligation? What are the specific sums that Her Majesty's Government are now spending on research and development into quieter aircraft?

I regret that the right hon. Gentleman has not had the letter, but I am pleased to give the House the information that he requested. The present level of expenditure is £1·25 million in the current financial year towards general research, with £750,000 in addition on improvements in the noise characteristics of the RB211 and the M45H engines.

Does my hon. Friend agree that these are very small sums compared with the amount envisaged for laying concrete on mud? Will he direct his attention to financing retrofits for existing power plants in service, such as the Spey, which at present manufacturers have to finance largely by themselves?

I think my hon. Friend will accept that the cost of research into retrofitting does not amount to a great deal. For example, the programme that the British Aircraft Corporation and Rolls-Royce discussed with me amounted to only £600,000. As the profits of BAC were in excess of £6 million, it did not seem unreasonable that it should fund this work from its own resources, particularly in view of the market that could exist for such a product. However, it is not the cost of developing the technology that is expensive. There are much more substantial costs in operating retrofitted aircraft once the work has been carried out and it is this aspect of the problem that makes one think carefully before reaching conclusions.

Even taking into account the costs that the hon. Gentleman has mentioned, are not sums of £750,000 and £1·25 million paltry compared with the proposed expenditure on Maplin? What does the "think tank" have to say about that?

The two are not totally comparable. As the House will appreciate, the purpose of developing a third London airport is to deal with a demand stretching through the rest of this century and using both quiet and relatively noisy aircraft. The question is what one does about that generation of aircraft, relatively noisy and with a relatively short life left, for that period during which they continue to exist. So the two issues cannot be equated. There is not the slightest doubt that one has to look at this matter carefully and bear in mind that the sort of figures I have mentioned for research into hush-kitting are as nothing compared with the airline penalties that would have to be paid by the general public for operating such aircraft that would result from such treatment.

On a point of order, Mr. Speaker. In view of the unsatisfactory nature of that reply, I beg to give notice that I shall raise the matter on the Adjournment.