Air Ministry specifications called for an aeroplane capable of flying more than twice as fast as any existing aircraft. At the time, no aeroplane had ever exceeded the sound barrier though there were unconfirmed reports of Spitfires and Mustangs going through the sound barrier in steep dives1.

Dubbed the Miles M.52, the secret aircraft would be designed for a speed of 1,000mph, with the ability to climb to 36,000 feet in 1.5 minutes.

In 1946 a team of American engineers from Bell Aviation visited the top-secret research facility of the Miles Aircraft company. The British government instructed the company to co-operate fully with the Americans, in return for data on the United States' own supersonic programme.

It is known that the Bell company had been having serious problems with control of their aircraft as it approached the sound barrier. The Miles team had overcome this snag with a completely new idea - the all-flying tailplane.

Basically, up until then, the horizontal tailplanes of all aircraft had been fitted with small flaps on their trailing edges to aid with vertical stability. The all-flying tailplane did away with these flaps, which were just not large enough to counteract the enormous forces encountered at supersonic speeds, and designed an aircraft where the entire horizontal tailplane pivoted, thus giving a much greater movable surface area with which to control the vertical pitch of the aircraft. This was a significant breakthrough, in fact Chuck Yeager is on record as saying that the single most significant contribution to the final success of the Bell XS-1 was the all-flying tailplane.

Within a few weeks of the American's visit, the Air Ministry Director of Scientific Research, Sir Ben Lockspeiser, cancelled the British supersonic project, saying:

    ...in view of the unknown hazards near the speed of sound ... [it is] considered unwise to proceed with the full-scale experiments.

Despite 90% of the design work being completed and half of the construction finished, the project fell, apparently due to a Treasury savings measure.

The Air Ministry ordered Miles to break up all jigs6 and to send all their design data to Bell Aviation. As it seems likely that the M.52 would have been flying by the summer of 1946, and since it would most likely have achieved its specified performance, it is hard not to believe the British government was pressured by the Americans to cancel the M.52 project.

This allowed the US become the first 'through the barrier', in October 1947, using the rocket-powered M.52 lookalike, the Bell XS-1. As an added bonus, the Americans' first jet engine, the General Electric Type 1, drew heavily on the designs of the British jet.

Make sure of your facts first Jake. I knew a lot of people involved with Miles Aircraft including my brother-in-law & late father-in-law. Being brought up within a stone's throw of Shoreham Airport where the company was based I've been an admirer of this talented family of aircraft designers since I was a young boy. A lot of bad feeling was caused by the sudden cancellation of the M.52 project & the company being compelled to give all its research data to the USA. I've read that this data was sent to Bell Aviation & other interested US companies. It's quite likely that they did in fact 'borrow' the idea of the all-flying tailplane or stabilator for the Bell X-1.

However, it's debatable who was responsible for the all-flying tailplane. The idea of all-moving flying surfaces is as old as manned flight itself. The Wright Flyer had a an all-moving fore plane which worked on the same principle, as did the Bristol Boxkite & other similar flying machines. Here's a photo of the Boxkite replica operated by the Shuttleworth Collection which was coincidentally built by Miles Aircraft Ltd for the film "Those Magnificent Men" http://www.military-aircraft.org.uk/other-military-aircraft/bristol-boxkite.htm

Several WWI types featured a conventional all-flying tailplane including the Fokker E.III that first appeared in 1915. http://www.ww2aircraft.net/forum/album/showphoto.php?photo=12459
Nothing much is new in engineering or aviation.

I was just irritated that the Americans seem to have completely overlooked the role that the British engineers had in this.  

I found this interesting article on the M.52 at the Museum of Berkshire Aviation website. http://museumofberkshireaviation.googlepages.com/high_speed_research.pdf

Note that the article was originally published in the October 1946 edition of The Aeroplane Spotter. This was not long after the project had been cancelled (in February 1946) but a whole year before Chuck Yeager broke the Sound Barrier in the Bell X-1 (14th October 1947). The "movable tailplane" is addressed as is the possibility of "some form of jet directional control". I think this proves that these ideas were not as revolutionary or secret as some people would have us believe.