The E.28/39 was the product of a specification which had been issued by the Air Ministry for a suitable aircraft to test the novel jet propulsion designs that Frank Whittle had been developing during the 1930s.

Gloster and the company's chief designer, George Carter, worked with Whittle to develop an otherwise conventional aircraft fitted with a Power Jets W.1 turbojet engine.

Following initial satisfactory reports, these aircraft continued to be flown to test increasingly refined engine designs and new aerodynamic features.

The E.28/39 contributed valuable initial experience with the new type of propulsion and led to the development of the Gloster Meteor, the first operational jet fighter to enter service with the Allies.

The first prototype continued test flying until 1944, after which it was withdrawn from service; in 1946, it was transferred to the Science Museum in London, where it has been on static display ever since; full-scale replicas have been created.

Independently, Whittle had also been producing several proposals for a high-altitude jet-powered bomber; following the start of the Second World War and the Battle for France, a greater national emphasis on fighter aircraft arose.

[8] In September 1939, the Air Ministry issued a specification to Gloster for an aircraft to test one of Frank Whittle's turbojet designs in flight.

The armament equipment called for in this specification will not be required for initial trials but the contractor will be required to make provision in the design for the weight and space occupied by these items..."[10] Early on, Gloster's chief designer, George Carter, worked closely with Whittle, and laid out a small low-wing aircraft of conventional configuration.

Buttler[12] reports Gloster engineer Richard Walker considered a short fuselage would overcome structural, accessibility and maintenance difficulties and increase the maximum speed of the aircraft.

Whittle was dissatisfied with the slowness of production, probably caused by the Battle of Britain as the area around nearby Coventry was subject to high levels of German bomber activity.

[9] A fuel tank, containing up to 82 Imp gal (372.8 litres), was behind the cockpit, supposed to have been adopted as a countermeasure against the impact of negative g, which posed the risk of causing the engine to flame out, which was hard to re-light during flight.

[23] John Grierson, in 1971, called these "end-plates" and wrote that their purpose was to increase the fin area due to the problem of rudder blanking in a side-slip.

[24] On 21 October 1942, Sayer disappeared during a flight in a Hawker Typhoon, presumed killed in a collision and his assistant, Michael Daunt, took over testing of the E.28/39.

[22] The first prototype was fitted with the 1,700 lbf (7.6 kN) thrust W2/500 and was flown to 42,000 ft (13,000 m), but level speed at altitude was not attempted, due to fuel shortage.

The Gloster E.28/39 was later able to achieve high speeds, the highest being 505 mph (813 km/h) at 30,000 ft (9,100 m) with a W.2/700 engine and it proved to be a useful experimental aircraft with a "good climb rate and ceiling".

[27] A full-size replica has been placed on an obelisk on a roundabout near the northern perimeter of Farnborough Airfield in Hampshire, as a memorial to Sir Frank Whittle.

A full-scale model taken from the same moulds, with authentic paint scheme and detailing, has been built by members of the Jet Age Museum in Gloucestershire.