§ Helen Jackson
To ask the Secretary of State for Defence, pursuant to his answers of 30 March 1998,Official Report, column 414, if the military exercises were carried out over the Sheffield area; what regulations govern (a) military and (b) other aircraft breaking the sound barrier; and if the sonic booms detected by Edinburgh University Seismology Unit above Sheffield, on 24 March 1997 were the result of aircraft breaking the sound barrier. 
§ Mr. Spellar
It is not possible, twelve months after the date in question, to state precisely where military aircraft activity was being carried out. Records kept show only that aircraft were booked to carry out low flying over the Peak District between 2030 and 2107 hours local time on the evening of 24 March 1997. No low level flying is permitted over the Sheffield urban area, or any other major conurbation. Records of flying at medium level—between 2,000 and 24,000 feet—are not maintained so it is possible that there were aircraft in the area at medium level.
The regulations governing military aircraft flying at supersonic speeds are contained in the Joint Service Publication entitled 'Military Flying Regulations', an extract of which was provided in the answer I gave her on 1 April 1998, Official Report, columns 547–48. The regulations which apply to civil aviation are a matter for my hon. Friend the Parliamentary Under-Secretary of State for the Environment, Transport and the Regions.
As for the sonic event detected by the British Geological Survey at Edinburgh University, I refer my hon. Friend to the answer I gave her on 30 March 1998, Official Report, columns 414–15.