XH648 was originally built as a B1 and delivered to 57 Squadron at Honington in 1959. Shortly afterwards it went to HP at Radlett for conversion to B1A status, which involved fitting ECM equipment and new engines. In 1965 it was converted by HP into a two-point tanker, making it a B(K)1A, and so served in its final years as a fueller until retirement to Duxford in June 1976.