VT935 as the P.111a, in an overall yellow colour scheme with a black cheatline running from the intake to the mid-span wing leading edge. By this time it had a set of four airbrakes fitted to reduce its fearsome landing speed.

View of the Boulton Paul P.111/111a prototype VT935, showing its compact delta planform and distinctive flattened elliptical intake. The aircraft is seen with airbrakes open

VT951, the P.120, was designed to investigate the interaction between a delta wing and a horizontal tailplane. It was painted in the colours seen here - gloss black with a yellow cheatline - in order to steal the 1952 Farnborough Show limelight from Avro’s blue and vermilion pair of 707 research deltas.

Three views illustrating the P.111’s stages of wingtip expansion; they increased the span from the basic 25ft 8in (left) to 29ft 8in, and ultimately to 33ft 6in.

The P.120 as originally rolled out at Pendeford in July 1952, in natural metal finish.

View of the Boulton Paul P.111/111a prototype VT935, showing its compact delta planform and distinctive flattened elliptical intake. The aircraft is seen taxying at the 1951 Farnborough Air Display.

View of the P.111 prototype VT935, which made its maiden flight in the hands of Boulton Paul chief test pilot A. E. "Benn" Gunn at A&AEE Boscombe Down on October 10, 1950. The characteristic nose-up ground attitude of the aircraft is apparent in this picture, as is the tall pointed fin - the extreme tip of which was designed to be removable for inflight comparison of sharp and blunt tip profiles.

VT935 in its original unadorned silver colour scheme.

View of the P.111 prototype VT935, which made its maiden flight in the hands of Boulton Paul chief test pilot A. E. "Benn" Gunn at A&AEE Boscombe Down on October 10, 1950.

Boulton Paul P.111, P.111a & P.120