We invented the movable tail plain that advanced the ability of controled fixed wing flight above Mk 1, guess what, we gave it to the US, FACT
Not a fact at all I'm very much afraid, the slab tail had been investigated by both sides prior to the Brits M.52, notably on the XP-42 and a modified Spitfire. The F-86E was the first supersonic capable aircraft to utilise the slab tail. The problem with using a slab tail on a supersonic aircraft was that it needed powered controls because of the pitching moments on the surface, the reason the X-1 didn't use a slab was because controls were manual, hence use of a normal elevator and trimable tailplane, no power source being available. The French used a slab tail on the Morane-Saulnier G in 1912, the Wright Brothers could possibly claim to be the first, though it was at the front (canard) rather than the back.
