The European Union transport commissioner, Siim Kallas, has described as "unacceptable" the severe disruption experienced by thousands of people in northern Europe trying to travel in the current wintry conditions.
It is three days since there was any significant snowfall in London, but Heathrow Airport is still facing disruption.
Frankfurt Airport, Germany's biggest, had to suspend flights for a few hours early this morning after fresh falls of snow.
In Cologne, two railway workers were killed during the night when they were hit by a train as they tried to de-ice the track.
Boris Johnson is the mayor of London.
First broadcast 21 December 2010