Having travelled on countless Heathrow flights in all directions, long haul to domestic, over the years, and therefore encountered countless fellow seatmates over this time, I am actually astounded at this figure of 37% for transfer traffic. In fact I cannot recall the last transfer pax I met on a flight, in or out, and that includes on many domestics which for some reason are regularly said to exist "primarily" for transfer traffic. More than half the passengers were from various UK points, and of overseas visitors just about the whole lot had been over to London & the South-East, which really puts the kosh on claims of Birmingham etc that they could take the traffic - I think many such visitors probably couldn't even spell Birmingham, let alone have any desire to take an air service to there.