14:00HRS: Birmingham Airport has closed until at least 18.00 hrs due to heavy snow. Its website has crashed due to heavy traffic.
London Heathrow has been forced to close one runway for snow clearing, leading to flight delays and cancellations.
The airport admitted several services had been hit this morning, but it said this was largely due to adverse weather elsewhere.
British Airways has taken the unusual step of offering passengers due to travel to or from any UK airport over the next three days the option to change their flight, free of charge, amid fears of weather-related mass disruption.
Passengers booked on BA flights, today, tomorrow and Sunday can defer their journeys to any time between January 24 and February 10. They need to contact the airline's call centre to change their booking.
The Met Office has issued weather warnings across the UK today, with south Wales likely to see the heaviest snowfall.
Bristol and Southampton Airport are closed this morning. Southampton said it would not reopen until 1500hrs at the earliest.
Cardiff Airport said it had been forced to cancel a handful of flights this morning due to a significant amount of snow and the M4 was closed at Junctions 36 and 37 in both directions.
EasyJet is also warning of possible disruption at Gatwick, Luton and Stansted, although all three airports are currently operating as normal.
Friday, January 18, 2013