Saunders - Roe SR . 177 The Saunders - Roe SR . 177 was a 1950s project to develop a combined jet - and rocket - powered interceptor aircraft for the Royal Air Force and Royal Navy . The German Navy also expressed interest in the project , which was cancelled due to changes in Britain ' s military policies in 1957 . A much larger development was studied under the SR . 187 project for Operational Requirement F . 155 , but this work was also cancelled in 1957 , after approximately 90 % of the first prototype had been completed . Design and development . In 1952 , Saunders - Roe had won a contract to develop a similar aircraft , the Saunders - Roe SR . 53 . However , as development progressed , the shortcomings of the design became increasingly evident . Most particularly , as with the German rocket - powered interceptors of the Second World War , the range and endurance of such an aircraft were limited by the high rate of fuel consumption by the rocket engine . However , as turbojets developed and became increasingly powerful and efficient , soon new powerplants were available that would make the aircraft more practical . The SR . 177 began as an advanced design concept for the SR . 53 , but when a development contract was issued by the Ministry of Defence ( specification F . 155 ) , the project was given its own designation . The most significant difference between the two aircraft was the use of a jet engine with nearly five times the thrust of the one chosen for the earlier aircraft . This meant that while the SR . 53 relied mostly on its rocket engine for climbing , the SR . 177 would be able to add considerable endurance by conserving use of its rocket for the dash towards a target only . It was expected that the added endurance would allow the SR . 177 to perform roles other than pure interception , and these were expected to include strike and reconnaissance . The SR . 53 design was considerably enlarged to accommodate the new engine , and the original sleek lines were forfeited for a large , chin mounted intake to supply it with air . Funding was secured in July 1956 for a total of 27 aircraft , and the first was expected to fly by April ( later , October ) 1958 . However , 1957 was to see a massive re - thinking of air defence philosophy in the UK , outlined in the 1957 Defence White Paper which called for manned combat aircraft to be replaced by missile s . By the time that the programme was axed later that year , the aircraft had proceeded little past mock - up stage . In 1957 a development contract for the SR . 177 was announced for its use with the Royal Navy . Work on the aircraft continued a little longer , however , in the anticipation of continued interest from Germany . The British Ministry of Supply agreed to continue funding development of five of the six prototypes , but nothing was to come of it . The German government had changed its priorities from looking for an interceptor to a strike fighter , leading Saunders - Roe to redesign the aircraft for this role . This was followed immediately by another redesign when Rolls - Royce successfully convinced the German government to replace the de Havilland engine intended for the SR . 177 with the Rolls - Royce RB . 153 . Even with Heinkel preparing to manufacture the aircraft locally under licence , Germany withdrew support in December 1957 . The Minister had visited the German government in November 1957 as the Germans wanted the arrangements to be between governments instead of between their Government and Saunders - Roe . Cancellation . Of the remaining aircraft under consideration the West German Government chose to purchase the Lockheed F - 104 Starfighter instead to meet the role of " high - altitude reconnaissance machine , a tactical fighter - bomber , and an all - weather fighter " , along with most of the European governments . This Lockheed coup , known as the " Deal of the Century " , caused major political controversy in Europe and West German Minister of Defence Franz Josef Strauss was almost forced to resign over the issue . During later investigation into Lockheed ' s business practices it was discovered that Lockheed had paid out millions of dollars in " sales incentives " in each of these countries to secure the deal . Prince Bernhard of the Netherlands confessed to taking more than one million USD in bribes from Lockheed to buy the F - 104 . With the withdrawal of German interest and no requirement for the SR . 177 by the RAF , the existing Royal Navy requirement was considered not worth proceeding with and the Ministry of Supply cancelled the project . Saunders - Roe announced an expected 1 , 000 redundancies as a result .