Heathrow and Gatwick rail services hit by Christmas engineering works
Holidaymakers face travel chaos over the festive period as rail links to Britain's two busiest airports are severed.
At Heathrow Airport the normal one-day closure on Christmas Day will be extended by three days due to Crossrail works.
Neither Heathrow Express nor Heathrow Connect trains will run from London Paddington station during the period.
Train operator Great Western Railway said services will be disrupted "as part of a large programme of engineering in the Thames Valley needed for the launch of Crossrail in 2019".
The disruption at Gatwick will last even longer, with the main line serving the airport blocked for 10 days due to engineering works.
The last Gatwick Express train of the year will leave London Victoria station at 9.15pm on Christmas Eve and the service will not restart until January 4.
On Boxing Day passengers can travel by train to East Grinstead and then catch a rail replacement bus to the airport, while from December 27 a train will operate direct to the airport via Horsham. But both options are expected to take three times longer than the usual 30-minute Gatwick Express service.
The work to replace a major railway junction at Purley will also cut off direct rail services from Brighton to the capital. Passengers in the coastal resort have been warned that the journey by a combination of train and bus will take up to two and a half hours, compared with the standard service which is under an hour.
Stephen Joseph, director of the Campaign for Better Transport, said: "These engineering works will of course cause huge problems for travellers and I suspect the decision has been taken to inconvenience airline passengers rather than inconvenience commuters.
"What these closures highlight, however, is the lack of surface transport options to both Heathrow and Gatwick, which is something the Government is still failing to address in its plans for airport expansion."
A Network Rail spokesman said: "Improving rail links to our major airports is absolutely vital for passengers, visitors and our economy. The work we're carrying out this Christmas has been planned in close collaboration with both Heathrow and Gatwick and the train operators which serve them.
"There will be rail and bus links to Gatwick but journeys will take longer, while London Underground links to Heathrow remain open."
National Express is operating coach services to both airports throughout the festive period, while London Underground will service Heathrow when the Tube network reopens on December 27.
Across the country there are no trains on Christmas Day and only certain services will run on Boxing Day.
There are several cases of major disruption being caused by engineering work after this period, such as t he West Coast main line being closed between Crewe and Stafford until December 29.
Passengers travelling to the South West and South Wales will endure extended journey times because of the line closure between Paddington and Slough, which is affecting Heathrow.
There was severe disruption last year when engineering work on the lines from King's Cross and Paddington overran, delaying travellers on the first Saturday after Christmas.
Travellers wanting to use the East Coast main line were advised to go to Finsbury Park in north London, which led to overcrowding.