On 11 May 2009, a Boeing 747-400 being operated by British Airways on a scheduled passenger flight from Johannesburg to London Heathrow experienced a stall protection system activation at rotation during a night departure in VMC which continued for a short time after the aircraft became airborne. A loss of lift was apparent and the flying characteristics of the aircraft were abnormal. Rate of climb was reduced by the PF, the First Officer, which resulted in stick shaker activation becoming intermittent. Then, shortly after the landing gear had been selected up, stick shaker activations ceased altogether and normal flying characteristics were restored. Being unsure of what had caused the event, but suspecting some sort of problem with both No 2 and No 3 engines, the flight crew declared a ‘PAN’ to ATC and decided to return to the airport of departure where, after fuel dumping, an uneventful landing was made about two hours after departure. None of the 283 occupants was injured and the aircraft was undamaged.