Airports operator BAA today blamed the London bombings and a wildcat strike by catering staff for fewer passengers passing through Heathrow airport in last financial year.
BAA, which owns seven UK airports including Gatwick, also pointed the finger at a softening national economy and higher oil prices for the drop.
A total of 67.4 million people passed through the four terminals at Heathrow during the year to March - down 0.3% on 12 months earlier.
In contrast, Gatwick had its best year on record with 3.28 million passengers passing through the airport to stand 2.6% higher than the previous year.
The boom in low-cost travel benefited its other UK airports such as Stansted, meaning that BAA handled 144.6 million people over the past 12 months - up 2% on the previous year.
But cancellations caused by heavy snow in Scotland and the north-east combined with Easter falling later than last year meant BAA saw passenger numbers fall by 1.3% in March to 11.4 million.
In Scotland, Aberdeen enjoyed the strongest annual growth at 9.5% while Edinburgh's passenger figures were up 5.6% and Glasgow lifted 2.4%.
Southampton saw a gain of 20.1% to 1.9 million passengers.
BAA is currently the target of a takeover bid from a consortium led by Ferrovial, the Spanish infrastructure group. It rejected an offer of 810p a share on Friday.
Fearing Ferrovial or a rival bidder could return with a much higher offer, closer to 900p a share, unconfirmed reports suggest BAA has prepared plans for a special dividend of up to £1 billion to keep shareholders onside.
The consortium, which includes a Canadian fund manager and the private equity investment arm of the Singapore government, has held meetings with the UK government and the Civil Aviation Authority since revealing its intention to bid.
It has also held an initial meeting with the trustees of the BAA pension scheme.
BAA told Ferrovial that its offer worth £8.75bn "did not begin to reflect the value of BAA's unique portfolio of airport assets".
