You will see from my location that I live at the 'gap' on the approach to Newcastle EGNT Runway 07 where the military North - South corridor crosses. Approaching Civils have to be at 'at least 3500feet' whereas the military guys can (and do) alternate lower and higher. We HAVE had an actual air-to-air involving two military a/c (one landed at EGNT with a damaged tail whilst the other crashed after the crew ejected safely).
One day I saw a light GA (probably a Warrior) heading inward when a Tornado flew across (and slightly below) the GA. I suspect the GA pilot may NOT have seen the Tonka (due to the instrument panel). I 'phoned Newcastle to be told that only the relative crews or an ATCO could register an Airprox . . .
They were CLOSE - but obviously there was no collision.