6 Feb 1979 I was the Tower Controller. The BAL B737 at the old Alpha holding point helpfully said 'I say, that aeroplane has crashed!'. I think I replied 'so it has' as I pressed the crash alarm. Left MG collapsed as it was rolling down the runway. It left the paved surface and ended up on the south side. During the recovery process all the gear collapsed!
It was taken by road to Leavesden where it was subsequently repaired by Eagle Aviation.
Not my pic, probably DG.