In July 1934 at a meeting chaired by Air Commodore Tedder, Air Ministry Science Office Captain F.W. ("Gunner") Hill presented his calculation showing that future fighters must carry no fewer than eight machine guns, each capable of firing 1,000 shots a minute. Hill's assistant in making his calculations was his 13-year-old daughter. Of the decision to place eight machine guns in fighters, Keith says 'The battle was brisk and was carried into very high quarters before the implementing authority was given. My Branch had made out a sound case for 8-gun fighters and if this recommendation had not been accepted and we had been content with half-measures, it might indeed have gone ill for us during the late summer of 1940'. Present at the meeting was Squadron Leader Ralph Sorley of the Air Ministry's Operational Requirements branch, who played an important role in the decision. In November 1934, the Air Ministry issued Specification F.5/34 which called for new fighter aircraft to be armed with a total of eight guns. However, by this time, work had progressed too far to immediately modify the planned four-gun installation. By January 1935, a wooden mock-up had been finished, and although a number of suggestions for detail changes were made, construction of the prototype was approved, and a new specification (F.36/34) was written around the design. In July 1935, this specification was amended to include installation of eight guns.