Nevertheless, from 1955 onwards, the UK had shown considerable interest in the Arrow. Desiring a high-performance interceptor like the Arrow, the RAF began the F.155 program in 1955, projecting a service entry date of 1962. As the program continued, it was clear the aircraft would not be ready by that date, and attention turned to interim designs that could be in service by the late 1950s to cover this period. At first, consideration was given to a "thin-wing" version of the Gloster Javelin that would provide moderate supersonic performance, along with the extremely high performance but short range Saunders-Roe SR.177.