Always an option, clearly today being the hottest at LHR
since records began, and with all flights now being completely full, has forced the issue.
Better that than off load some pax.
Sure we had a hot summer in 1976, we were not flying Concorde to JFK
then, and a few days in 1990, again flights would not be certain to be completely full, though this week seems to have topped those years, it certainly feels that way-I've taken 3 showers so far and I've not even been doing that much!