The Royal Navy's new Joint Strike Fighter may be unable to land on an aircraft carrier because of a design flaw according to a Pentagon report leaked to a national newspaper. Documents obtained by The Sunday Times reveal the report -- called the F-35 Joint Strike Fighter Concurrency Quick Look Review -- has identified a serious flaw in the aircraft's design. It reveals eight simulated landings of the new variant all-purpose jet, known as the F-35C, failed because the "arrestor" hook, used to stop the plane during landing, is too close to the undercarriage at just seven feet away, compared with 18ft on existing US Navy aircraft. The report concludes that a "significant redesign" of the aircraft is needed and that the future of the aircraft is at risk. It also suggests the new fighter may be unable to fire British Asram air-to-air missiles and is untested in several other areas. It says if a redesign proves too costly and complicated the entire F-35C programme may have to be scrapped. The Ministry of Defence has declined to comment on the leaked report but Defence Secretary Philip Hammond "discussed a number of issues including the Joint Strike Fighter" with his counterpart Leon Panetta in his recent visit to Washington. A spokesman said: "We are taking delivery of our first Joint Strike Fighters for test and evaluation purposes this year and are committed to purchasing the carrier variant of the JSF. Our plans remain on track to have a new carrier strike capability from around 2020." A spokesman said: "We are taking delivery of our first Joint Strike Fighters for test and evaluation purposes this year and are committed to purchasing the carrier variant of the JSF. Our plans remain on track to have a new carrier strike capability from around 2020."