BAA said the drop in passenger traffic in December was almost entirely due to the severe weather.

Passenger numbers were down 9.5% at Heathrow, BAA's largest airport, but all the firm's airports saw steep falls in traffic, with user numbers at Southampton airport down 22% and Edinburgh down 18.4%.

Of the £24m hit from the snow, £19m was accounted for by Heathrow.

The cost was caused by lower revenues as well as higher expenses, particularly in supporting delayed passengers, BAA said.