asked the Under-Secretary of State for Air the average speed in miles per hour of the machines taking part in the recent air manoeuvres over London?

I must apologise to the House for the length of the reply which I must necessarily make. A figure based on the average speed of types as diverse as interceptor fighters and heavy night bombers employed in a particular exercise would be so misleading as to be hardly worth calculation. I assume that what my hon. Friend requires is a reassurance as to the speeds of our service aircraft for Home Defence. I may therefore say that, apart from certain types with a better performance already flying but still in the development stage, the speed of the latest type in production, supply of which is now commencing to squadrons, is in excess of 230 miles per hour, and that the design of a new type is well advanced. This latter will give a markedly higher performance, though it would not be in the public interest to disclose precise particulars at this stage. I may add, since there has been much talk of the performance of certain foreign civil machines, that, if these latter were to be equipped with the means of self-defence which they at present lack, a substantial reduction in the maximum speeds commonly quoted for them would result.