Hundreds of passengers had to queue in the rain after the identification of a suspect package led to a part-evacuation of a terminal at the UK's biggest airport.
The package discovery just before midday led to long delays for passengers at Heathrow's Terminal 4 in west London.
Airport operator BAA said that the baggage incident had led to a decision to search all departing passengers again, with the departure lounge being partially evacuated. Long lines of passengers, who had to endure showers between bursts of sunshine, built up outside the terminal and departing flights were delayed.
A BAA spokesperson said: "A suspect bag was identified shortly before midday in Terminal 4. As an extra precaution, it was decided to perform secondary searches on all departing passengers at the aircraft gate.
"In order to facilitate the secondary search process, a decision was made by the police to partially evacuate the departure lounge and re-screen the passengers.
"This process will cause delays to some flights departing from Terminal 4. Contingency plans have now been activated to ensure that we are able to effectively manage the increase in resource that this secondary search requires."
Later, BAA said that there were no departing flights operating from Terminal 4 (T4), although planes were still arriving as normal.
British Airways said it had cancelled all its European departures from T4 from 3pm until the rest of the day, as well as cancelling all its T4 long-haul departures from 3pm to 9pm.
A BA spokeswoman added: "We have had to cancel 108 flights in total. Our flights to and from Terminal 1 at Heathrow are operating, but with some delays."
BA said those passengers affected could rebook, rebook with another airline or claim a refund.
