Passengers are being advised not to use a main London to Scotland rail line over Christmas due to one of a series of engineering projects set to cause severe disruption over the holiday period.
The work on the West Coast main line means the line will be shut between Euston station in London and Hemel Hempstead in Hertfordshire after the last trains on Christmas Eve until Monday December 29.
It will also be closed between Stafford and Crewe after the last trains on Christmas Eve until Sunday 28 December.
The closures are necessary as work continues on improvements in the Watford area and between Stafford and Crewe.
To minimise disruption Network Rail and the Virgin Trains and London Midland train companies are advising passengers to avoid the West Coast main line and use alternative routes.
Jim Syddall, acting route managing director for Network Rail, said: "There is never a good time to carry out this type of work and we have liaised closely with the train operators to plan for it to take place at a traditionally quieter time on the railway.
"We apologise for the inconvenience caused but the work is essential to improve the network and maintain reliable services for the millions of passengers who travel on the West Coast main line every year."
The West Coast closure is just one of a number of disruptions to services over Christmas and the new year, as Network Rail carry out a major programme of engineering work.
The disruption will affect services out of a number of main London stations including London Bridge, where there will be a 16-day part closure for work involving the £6.5 billion Thameslink programme.
From Saturday December 20 to Sunday January 4 Southern and Thameslink trains will not call at London Bridge and cross-London Thameslink Bedford-Brighton trains will not return until 2018.
Also, from Monday December 22 to Christmas Eve some Southeastern Charing Cross services will not call at London Bridge in the morning peak.
Another of the main London terminii affected over the holiday period is Paddington, where engineering work taking place between Southall and Slough west of London means some lines will be closed from 5pm on Christmas Eve until the end of Sunday December 28.
Services will also be affected by engineering work is taking place between Slough and Reading West/Tilehurst in Berkshire from Monday December 29 to Saturday January 3.
On the weekend of December 27/28 buses will replace trains between Ascot and Aldershot due to engineering work between these stations, while between December 27 and January 2 engineering work between St Albans and West Hampstead will cause disruption between Luton and Sutton and between Blackfriars station in London and Sevenoaks in Kent.
On December 27/28 engineering work taking place between Edge Hill and Earlestown/St Helens Central is closing some lines in north west England, while buses will replace trains on Arriva Trains Wales services between Shrewsbury and Hereford from December 27 to 29.
Other areas where engineering work is scheduled at times over the holiday period include Birmingham New Street and between Cambridge and Ely in East Anglia.
One train company running trains on Boxing Day, and for the second successive year, is Chiltern Railways which will be operating services between Bicester North and London.
Meanwhile, British Airways is preparing to take record numbers away for Christmas this year.
In the period December 12 to January 5 BA will be carrying around 2.7 million passengers, with Friday December 19 its busiest day with 129,000 customers flying.
The BA schedules include 267 flights on Christmas Day on which 37,000 turkey dinners will be served.
To BA destinations over the festive period are Dubai, Barbados, New York, Australia and Barcelona.
Ryanair is carrying more than 3.5 million customers between December 20 and January 6 - an increase of 500,000 customers over the 2013/14 holiday period.
Popular destinations include the Portuguese Algarve, the Canary Islands, Cologne and Prague.
On the roads, National Express is doubling the number of coach services on Christmas Day and operating a near-normal service on Boxing Day.
The company said that advance bookings for the period December 1 to January 4 were 7% up on the 2013/14 festive period.
The Southeastern and ScotRail companies will also be running some services on Boxing Day this year and Gatwick Express and Stansted Express trains will operate as well.
Michael Roberts, director general of the Rail Delivery Group, which represents operators and Network Rail, said: "Building a better, safer railway is something we do every day but major holidays are when significantly fewer people travel, and the industry has been working more closely than ever this year to ensure that disruption to passengers is minimised and people are kept on trains wherever possible."
He went on: "Fewer than 3% of services will be on replacement buses this Christmas, and a number of operators will be running services on Boxing Day in response to passenger demand.
"Rail staff will be working around the clock through the Christmas break to lay new track, renew signals, repair bridges and build new platforms, to deliver more and better services for Britain.
"People planning to travel over the festive period should look for information at their local station, check their train operator website or www.nationalrail.co.uk/christmas."