VC-10.
M.94 for the maximum high speed cruise (normally used)...hardly.
Friends at GF years ago mentioned it was never cruised above M.86.
The CV990 was normally cruised at M.88/90.
When fuel was cheaper, of course.
The VC10 and the CV990 disappeared from airline flying many years ago.
Yet the 'ole B707 still plugs along...at last count, 140 of 'em still flying, I believe.
At M.82.