The Accident.....
....... to which BOAC and tartare refer was a development aircraft being flown by a Major Rosberg and it happened at a Brit Aerospace airfield (Dunsfold - I think).
All the test flights were filmed at the time, hence the loss of the pilot was clear for all to see. A few years later, the RAF sought permission to use the film as part of a flight safety film they were putting together and BAe refused. However, they relented subsequently.
The film 'starred' the actor Richard O'Sullivan as a pilot and one of the scenes included a chap called Chris Humphrey, who was unfortunately killed before the film's release, demonstrating a Harrier to iirc the Swiss.