aviate 1138 and ORAC are both correct. The XB-70 crash did kill Maj Cross after Joe Walker's F-104 collided with it during a totally unnecessary photo shoot. And 'Lordy' Mountbottom indeed helped Wislon's lot to kill off the TSR2. As I once had the pleasure of telling him at Broadlands. :
Mountbottom: "In the RAF, eh, what do you fly?"
BEagle: "The Buccaneer"
Mountbottom: "Ah - a good aeroplane. The Royal Navy was very proud of it"
BEagle: "But we've only got it because the TSR2, vastly better in all respects, was killed off by political stupidity and we're stuck with old naval bombers instead!"
Mountbottom: "Hmm, must go. People to meet......"