John - ref below
"I would dispute that: on 21st March 1974 054 from 824NAS flew into a 220ft high cliff on the Lizard Peninsular when positioning at night at 200ft radalt hold (due to doppler plot slippage was the BOI finding). Why the radar failed to give an indication that all was not well was never established, all four on board were killed."
Was it not something to do with MTI that meant the land did not show on the screen?