At Boscombe Down in the late '80s 2 x 2250l tanks dropped off an F3 shortly after unstick. There was no fire when they hit the ground but monstrous contamination of the runway surface. We managed to get the aircraft shut down before the ADR over-wrote the incident. The cause was the EJ button inadvertently being pushed by the pilot as he selected the landing gear up (probably with the knuckle of his index finger). The result was a modification which set the front cockpit jettison buttons deeper into the panel; the standard of the aircraft to which this happened had buttons that were flush with the panel surface.