Yet another head has rolled in the wake of the Heathrow T5 fiasco. The airport’s managing director Mark Bullock has “chosen to leave his job”, after the forced departures of BA executives Gareth Kirkwood and David Noyes last month. And with yesterday’s news that British Airways is looking for a candidate to “one day” replace Willie Walsh, the airline's chief executive, it looks like the body count is set to rise further.