Although the Wyvern was designed as a turboprop-powered carrier-based strike aircraft, VR137 was built in 1947 at Yeovil as the seventh and last preproduction TF.Mk.1. It was the sole one fitted with a 2,690 hp Rolls-Royce Eagle 22 24-cylinder sleeve valve flat-H piston engine, but was never flown. Of the 127 built, this is the only survivor