The Hawker Siddeley HS.800 based on the Trident airliner which was tendered to meet OR.357. It is similar to the earlier Avro 776 but has keeping the Rolls-Royce Speys. The Operational Requirement was superseded by the RAF (again), to a less ambitious standard as OR.381, which was won by the another Hawker Siddeley submission, the Comet-based HS.801 which became the Nimrod.