BLEU (renamed the Operational Systems Division of RAE in 1974) continued to play a leading role in the development of aircraft guidance systems, using a variety of aircraft including DH Comet, BAC 1–11, HS 748 (to replace the Varsities, which had been the main "work horses" for BLEU experiments for more than a decade) and VC-10 until the closure of RAE Bedford in 1994.