This extract from the Operation Record Book (ORB) of 175 Squadron relates to this young man:     Pilot Officer Derek Leyland Stevenson flying this aeroplane:     on 19th August 1942.     The Adjutant's summary reads as follows:     and an extract that I've copied:   What these excited young men didn't realise was that what was taking place beneath them was one of the biggest tragedies of the war i