been working on a project to produce a suitable VTOL engine; this engine combined major elements of their Olympus and Orpheus jet engines to produce a directable fan jet. The projected fan jet harnessed rotatable cold jets which were positioned on either side of the compressor along with rotatable 'hot' jets which was directed via a bifurcated tailpipe. With a suitable engine already being developed, Camm and his team at HSA proceeded to develop the company's first VTOL aircraft, designated as the Hawker Siddeley P.1127. The P.1127 was envisioned as a subsonic VTOL-capable strike aircraft, while also serving to demonstrate and prove the capabilities of the aircraft's basic configuration and to validate the performance of the Rolls-Royce Pegasus engine that powered it. While financial backing was issued by NATO's Mutual Weapons Development Program to support development of the Pegasus engine, the British government were not forthcoming with funding. While HSA chose to go ahead with the P.1127 as a private venture, the Air Staff disagreed heavily over what requirements should be set out for a future RAF VTOL aircraft; some officers, such as the Chief of the Air Staff Sir Thomas Pike, advocated simplicity while others, such as the RAF operational requirements division, sought various performance demands of such an aircraft, particularly the capacity for supersonic flight. HSA was also interested in the prospects and feasibility of a more sophisticated development of the P.1127, knowing that a supersonic-capable VTOL aircraft would likely be more attractive to customers, there being a general perception at the time that supersonic aircraft held significantly more value than their subsonic counterparts. Consequently, on 13 April 1961, HSA decided to conduct preliminary work on a supersonic derivative of the P.1127 under the guidance of Ralph Hooper. This would result in a new design, designated P.1150, which was 50% larger than the preceding P.1127; it was proposed that a new performance-enhancing feature be adopted in the form of the plenum chamber burning (PCB) – similar to an afterburner, but acting only on the bypass air that discharged through the front nozzles. The P.1150 proposal broadly resembled its P.1127 predecessor despite major changes being made, including its revised fuselage, the adoption of a thinner wing, and an advanced version of the Pegasus engine. The Bristol Siddeley BS100 engine was equipped with a similar arrangement of four swivelling exhaust nozzles, the front nozzles of which were to be equipped