Heathrow was hit by Sars fears

BAA, which runs seven UK airports including Heathrow, Gatwick and Stansted, said traffic on the North Atlantic routes was down 7%.

Passenger numbers on flights to and from the United States are thought to have been hit by concerns over the Iraq war.

However, BAA said that, compared with previous global crises, there had been no overall dip in traffic at its airports as a result of the conflict and the Sars epidemic in Asia.

The company said there had been strong growth in European flights and on domestic routes.

Traffic to and from the Middle East picked up quickly following the end of the war in Iraq, BAA said.

But routes to countries affected by the Sars outbreak saw a 35% drop in passenger numbers.

Heathrow was particularly badly hit by the Sars scare, as it is the main hub for Asia Pacific flights.

Traffic overall at the London airport was down 4.2%.