South West Trains
Improvement works mean Southern and Gatwick Express services will be disrupted over the holiday periodGetty

This year is set to be the busiest Christmas yet for holidaymakers heading abroad for the festive season, but airline passengers will be hit with engineering works on railway lines heading to major London airports.

Travellers from Heathrow and Gatwick will face train cancellations over the Christmas and the New Year. Around 2.2 million people are expected to use trains during the period and around 5 million people flew abroad for Christmas from Britain last year.

Gatwick

Improvement works mean Southern and Gatwick Express services will be disrupted over the holiday period, impacting services between London and Gatwick Airport from 10pm on Christmas Eve until 4am on Monday 4 January 2016.

During these dates there will be no trains between South Croydon and Redhill. The Gatwick Express Service will be suspended, but it is possible to travel via Horsham – but this journey will take around 90 minutes instead of 30 minutes.

There will be some replacement bus services from East Grinstead from Boxing Day, from which the journey to Gatwick will take around 90 minutes.

An airport spokesperson told the Independent the engineering works were an "essential part of plans to double rail capacity by 2020".

Heathrow

The Heathrow Express from Paddington will be suspended for four days from Christmas Day due to Crossrail works. Neither Heathrow Express nor Heathrow Connect trains will run from London Paddington station during these dates.

Crossrail works will also disrupt services from Paddington to Slough on the same line, according to the Guardian.

A Heathrow Express spokesperson said: "This is due to essential improvement works being carried out by Network Rail. We are sorry for any inconvenience caused."

The Heathrow Express will be running every 30 minutes all day from Tueday 29 December to Friday 1 January. For more information, visit the website here.

Stansted

The Stansted Express will not operate on Christmas Day, but a reduced service will run on Boxing Day. A Saturday service will run on New Year's Day. Due to engineering work, buses replace trains between Stansted Airport and Liverpool Street on Saturday 2 January and Sunday 3 January.

Where else is major engineering work taking place?

According to National Rail, the following stations and routes will be disrupted due to major improvement work over the Christmas and New Year period. For more information, visit the website here.

London Liverpool Street

Doncaster area/Cleethorpes to Doncaster/Newark North Gate

Crewe to Stafford

London Cannon Street/Charing Cross/London Bridge

London Paddington to Reading (Crossrail)

London to Brighton