"Regarding BEA Airtours, I accept what all you pros above write but I had always had the impression they used to use the callsign "Tango". Anyone know how this belief might have arisen ?"
I seem to recall that BEA Airtours referred to their flights as "Tango" for passenger use. I can certainly remember hearing departure announcements for Tango + numbers on the PA at Gatwick. I assume that somebody in marketing thought that it would give the SLF the impression of something more inviting than a ride in a hand-me-down 707 or Comet. For ATC use it was always "Beetours".
NN