On 31 May 1985, 1D91 09:20 Gatwick Airport to Victoria Gatwick express formed of GLV, 8301, 8203, 8313, 73117 collided with 2L51 08:51 East Grinstead to Victoria formed of DEMU 1113 and 1309 travelling along the up fast main line from Clapham Junction. Train 1D91 was following 2L51 along the Up Fast line, through Clapham Junction station, at which the latter train had made a scheduled stop and beyond towards Battersea Park. 1D91 had closed sufficiently on 2L51 that the former passed a series of signals displaying a 'single yellow' caution aspect, at which the driver cancelled the AWS warning and continued, as he was entitled to, at a speed of around . Train 2L51 was then stopped for 1–2 minutes at signal VC552 displaying a red aspect. When that signal cleared, 2L51 was accelerating past it when it was struck from behind by 1D91 which had passed the protecting signal, VC564, at Danger.