The West was stunned when the Soviet Union dropped its first atomic bomb in August 1949 and a year later the Korean War showcased Russia’s incredible technological progress in the form of the MiG-15 – a fighter capable of besting anything the RAF could offer at that time. In the wake of the Second World War, funding for the RAF’s Fighter Command had fallen away dramatically but now there was an urgent need for new jet fighters to meet the threat of Russian bombers head-on.

The result was Operational Requirement (OR.) 329/F.155T and some of the most outlandish designs ever committed to paper.

Britain’s top aircraft manufacturers, including Hawker, English Electric, Fairey, Vickers Supermarine, de Havilland, Saunders-Roe and Armstrong Whitworth, set to work on designing powerful supersonic aircraft with all-new guided missile systems capable of intercepting a Soviet assault and shooting down high-flying enemy aircraft before they could unleash a devastating nuclear firestorm on British soil.

As told by Dan Sharp in his book Cold War Interceptor, the slender experimental Fairey Delta 2 had made its first flight a full year before the tender submission date for F.155T and the company naturally offered a straightforward development of this promising design for the competition -but it also harboured ambitions to go a step further.

The first Fairey Delta 2 to fly, serial WG774, made its first flight from 4.57pm to 5.23pm on Oct. 6, 1954. At Boscombe Down on Nov. 17, during the 14th flight of its test programme and having yet to go supersonic, the aircraft suffered engine failure at 30,000ft at 1.06pm and was brought in for a forced landing at 1.12pm. According to the crash report, issued on Nov. 22, pilot Peter Twiss “succeeded in landing the aircraft on the runway on the nose wheel and tail skid only. He ran along level for about 1000ft and only then slewed off the runway. The aircraft is now on its main undercarriage and will be brought back to Fairey works by road on Monday.

“There is some damage to the nose wheel, the underside of the rear fuselage and to the wing tips and ailerons. It is intended to remove the wing and check for distortion in the jigs. Until this is done it will be uncertain how much damage has been sustained.”

As investigations into the cause of WG774’s engine failure, focusing on fuel starvation, continued on Mar. 18, 1955, Fairey’s chief engineer Robert Lickley sent Ronald Andrew Shaw, Assistant Director of the Ministry of Supply’s Aircraft Research Department, a letter headed ‘ER.103 [Experimental Requirement ER. 103 issued on Sep. 26, 1950 which generated the Delta 2] Development’. He wrote: “As you know, we have been looking into developments of the ER.103, and the enclosed brochure is an attempt to summarise our thoughts and ideas.

“We have based it mainly on the fact that by making use of the lead-in time already available in the ER.103 prototype, a very high performance fighter can be available in squadron service, well in advance of any new type. The interim version would give much useful data, and would represent a research type of considerable value.

“The whole project would seem to fall into the shorter development stages now envisaged, but gains greatly by making use of aircraft research programmes already under way. Should you wish to discuss further any aspect of this, I would be very pleased to do so with you.” Scribbled at the bottom of Lickley’s original letter is a note from Shaw: `Spoke on telephone 22.3.55′.

The brochure itself set out a two-step programme. The Delta 2 was regarded as ER.103A and the next step was ER.103B, the interim experimental version mentioned in Lickley’s letter. This was to be slightly enlarged from the base model with a wingspan increase from 26ft 10in to 28ft, length increase from 52ft 3in to 54ft 4in and height from 10ft 2in to 12ft 4in. The engine would be replaced with either a de Havilland Gyron or Rolls-Royce RB.122, taking top speed at 45,000ft from Mach 1.49 to Mach 2.72.

If this proved to be successful, the final development would be a fighter powered by a Gyron and two d( Havilland Spectre rocket engines. Its size would be significantly increased, with a wingspan of 37ft 7in, length of 58ft 4in and height of 14ft 2in. The ‘A’ weighed 13,600lb and the ‘B’ 20,650lb, but the `C’ would tip the scales at 27,000lb. Speed at 45,000ft would drop slightly to Mach 2.54 and armament would be two Blue Jay missiles. It is evident that Lickley’s thoughts were now firmly fixed on F.155T.

The Delta 2 mock-up was still taking up valuable space at Fairey by Jun. 8, 1955, when the Ministry of Supply, whose position had previously been that it should be scrapped, wrote to the company to say: “Arrangements have been made for the Air Ministry to take over the mock-up of the above aircraft … the mock-up will be collected by Service transport from RAF Station Henlow on the 9th or 10th June. This letter authorises you to hand over the aircraft and engine mock-ups to the officer in charge of transport.”

The fact that the Air Ministry had taken over the Delta 2 mock-up, rather than see it scrapped, would seem to suggest a strong interest from the Air Staff in the aircraft as a potential basis for future fighters, even at this early stage.

Flight testing of WG774 had resumed on Jun. 26 but fuel system problems were experienced almost immediately and on Jul. 13 the aircraft suffered an engine failure during the early part of its take-off run. The engine was removed from the aircraft and sent back to Rolls-Royce for detailed examination. A de-rated engine was fitted in the meantime and subsonic flights resumed – 26 being carried out between Aug. 23 and Sep. 26. The Delta 2 had not yet broken the sound barrier.

When the Oct. 6 deadline for submission of the F.155T tenders came, uniquely among the competitors, Fairey offered two designs. The first was a direct development of the Delta 2 and amounted to a two-seater version of the ‘ER.103C’ outlined in Lickley’s brochure of seven months earlier. The second was something new which – though still based on Delta 2 technology – represented a bigger and riskier step forward.

During adjudication, the ER.103 development tended to be referred to as either the ‘Fairey Small’ or ‘Fairey Little’. The title on the brochure was simply ‘The Fairey Fighter Aircraft (ER.103 Development)’ and the three-view drawing was titled ‘The Fairey Two-Seat Fighter (ER.103 Development)’. The second proposal, much larger and more powerful, was referred to as ‘Fairey Large’ or ‘Fairey Big’.

The ER.103 development had its own brochure but there was no accompanying text – just drawings and technical statistics. This ‘Fairey Small’ had the ER. 103C’s single Gyron engine with two Spectre rocket motors but slightly different dimensions, being 56ft 3in long and 14ft 3 in tall though the overall wingspan was identical at 37ft 7in.

However, as the ‘Fairey Large’ brochure explained: “A single engine type was just possible (see our alternative submission); designed round the de Havilland weapon only, but both altitude performance and range would be marginal.”

The Delta 2 would surprise everyone – including Fairey itself — by breaking the absolute World Speed Record by a huge margin in March 1956 (the previous official air speed record was 822.1 mph by Horace Hanes in a F-100C Super Sabre. On Mar. 10, 1956, Peter Twiss flew established a new record with the FD2 of 1,132mph. This was an increase of approximately 37% on the previous record) but in October 1955 its potential was viewed in a much more pessimistic light.

Testing of the Delta 2 was also carried out in France for some time, in part due to Fairey’s good relations with Dassault Aviation of France and the French Air Force. In October and November 1956, a total of 47 low-level supersonic test flights were conducted from Cazaux Air Base, Bordeaux, France; a detachment of Dassault engineers closely observed these trials, learning a great deal about delta wing aircraft from the Delta 2. Dassault went on to produce the MD.550 Mystère-Delta design, which as aviation author Derek Wood notes “bore a striking resemblance” to the Delta 2; the MD.550 design would proceed to be manufactured as the successful Dassault Mirage III fighter. Wood credits the Delta 2 as having served to confirm Dassault’s theories and supporting the designing and development of the Mirage III.