Rail users will face a hugely disrupted service over Christmas and the New Year, with "essential engineering works" forcing widespread line closures, reduced services and rail replacement buses on dozens of routes.
Among the services affected are the Gatwick Express, and mainline routes to Heathrow Airport and Manchester Airport, with the disruption set to last from Christmas Day to the end of New Year's Day.
The cancellations on the Gatwick Express, which runs from London's Victoria station to Gatwick Airport in West Sussex, are due to a major tranche of engineering work being carried out at Gatwick station, at Victoria and between Redhill and Purley in Surrey.
This extensive work will also affect services operated by the First Capital Connect (FCC), First Great Western (FGW) and Southern train companies. Certain trains will not run over the festive period, with bus replacement services operating on some routes.
Engineering work is taking place between Paddington station in London and Slough in Berkshire from December 27 to January 3. This will mean disruption to some FGW services, while some Heathrow Express services will be affected from December 30 to January 1.
FGW passengers will also have to put up with engineering work between Oxford and Hanborough from December 27 to 29, while FGW services and those run by the CrossCountry are being disrupted by engineering work between Reading and Basingstoke from December 27 to 30.
FGW passengers will have to use buses instead of trains between Maidenhead and Marlow from December 27 to 29 due to engineering work, while FGW services will also be disrupted from December 29 to January 3 by engineering work between Reading and Didcot Parkway.
A major £19 million upgrade at Gravesend station in Kent will mean the Southeastern company will not be able to run any trains from or through Gravesend between December 22 and January 5. Buses will replace the Gravesend trains
The Gravesend work will also affect Southeastern's high-speed services.
Engineering work between Retford and Lincoln and between Gainsborough Lea Road and Lincoln will mean buses replace trains between Doncaster/Retford and Lincoln from December 21 to January 5.
From December 23 to 27 there will be engineering work between Manchester Piccadilly and Manchester Airport stations with lines closed at various times. Buses will replace trains on some routes during this time. There is also engineering work in the Manchester Victoria area which will affect Northern Rail services between December 27 and January 1.
Engineering work from December 28 to 30 will mean East Midlands Trains passengers will have to take buses instead of trains between Spalding and Sleaford in Lincolnshire.
Buses will replace trains on parts of London Overground between December 23 and 27 due to engineering work between Surrey Quays and New Cross Gate/New Cross.
Platforms 1-9 will be closed at Waterloo station in London from December 27 to 29, with disruptions to services by South West Trains.
On the Victoria, Gatwick and Surrey disruptions, Network Rail Sussex route managing director Tim Robinson said: "These are three significant infrastructure upgrades which have been carefully planned to take place at the same time to keep disruption to a minimum."
One good bit of news for travellers is that the Chiltern train company will for the first time be running some services on Boxing Day. Its trains will operate for around 12 hours, with the first train northbound from London to Bicester North at 8.15am and the last to Princes Risborough at 6.45pm.
Southbound, the first train will run from High Wycombe to Marylebone station in London at 8.29am and the last will run from Bicester North to Marylebone at 6.57pm.
On the Tube there is track replacement work at Earl's Court in west London over the festive period. There will be part closures on the District and Jubilee lines between December 27 and 30, while a section of the Northern line will be shut on December 28 and 29.
Michael Roberts, director general of rail industry body the Rail Delivery Group, said: "We are living through one of the biggest investment programmes in the history of the railway.
"Passengers and businesses are benefiting from multimillion-pound projects such as King's Cross and Birmingham New Street as well as thousands of vital smaller schemes to improve tracks, signals and stations."
He went on: "Building a better network is something we do every day. But Christmas and other major holidays are when the railway is less busy than on a typical weekday. So we use these periods to carry out particularly important improvements.
"A great deal of care goes into minimising the impact of this vital work and to keep people on trains wherever possible. By planning ahead, the vast majority of passengers travelling by rail over the festive period can expect to travel without disruption."
Additional reporting PA