Millions of train passengers will face serious disruption on the UK’s main railway lines to and from London over the upcoming Christmas period, with warnings that they should start planning alternative routes now.

This year’s festive season will be the first since 2019 that has not been afflicted by Covid, rail strikes or both – but key rail stations and intercity lines will be closed due to engineering work.

Work on the controversial HS2 project will lead to the closure of London Paddington station for a six-day spell. Some Great Western trains from Wales and Cornwall will be diverted to London Euston – adding pressure on a station described last week as dangerously overcrowded.

Euston will also be the start or end of the journey for many travellers to and from Leicester, Nottingham, Derby and Sheffield.

The line north from London St Pancras International, the usual terminus in the capital, will be closed for nine days for bridge repairs. During this time, passengers will travel on Avanti West Coast or London Northwestern from Euston to Milton Keynes, from where rail-replacement buses will run to Bedford.

Helen Hamlin, Network Rail’s director of system operations, said: “The festive period is a unique opportunity, when fewer people are travelling, to do big pieces of work to make services better, more punctual and more reliable.

“The major projects we’re undertaking would otherwise take many weekends to complete and cause much more disruption.

“Whilst roads are busier during the holidays, it’s actually one of the quietest times on the railway, meaning we can improve things whilst causing less disruption to passengers and freight flows.”

The work involves renewing 45 sets of points, replacing four bridges, installing 40km (25 miles) of new signalling cables, and renewing 17 level crossings. There will also be work on drainage projects in an attempt to stop line closures due to flooding, which have dogged passengers’ journeys in recent weeks.

The worst-affected routes are:

Midland Main Line

London St Pancras International to Luton (including the airport), Leicester, Derby, Nottingham and Sheffield

No trains from 21 to 29 December inclusive due to the replacement of the Agar Grove railway bridge in Camden, north London.

Hourly East Midlands trains will run from Sheffield, Corby and Nottingham as far south as Bedford, for rail-replacement buses to Milton Keynes Central. Intercity journeys to/from London are expected to take an hour longer, and pressure on London Euston will be intense, with extra travellers diverted from the Midland Main Line and London Paddington passing through.

Thameslink trains will be badly affected, with shuttles running south and north of London St Pancras.

Great Western line

London Paddington to Heathrow, Reading, South Wales and the West of England

After Christmas Eve, no mainline trains will run to or from London Paddington station until Monday 30 December. The cause: work on HS2 at Old Oak Common. In addition, Network Rail will use the opportunity to improve track, signals and overhead wires between Paddington and Reading.

Instead, passengers from Penzance, Plymouth, Exeter, Swansea and Cardiff will have hourly trains to and from London Euston.

National Rail says: “These services will not stop at Reading and you will also require a seat reservation for these trains.”

Normally anyone with a flexible “anytime” or “off-peak” ticket can step aboard a train so long as they don’t mind standing. This will not be possible on GWR links to Euston.

Links from Bristol, Bath, Oxford and Worcester will run as far as Reading, where London-bound passengers can change for GWR services to Ealing Broadway in west London or South Western Railway links to Waterloo.

The last Night Riviera sleeper trains before Christmas will run between Penzance and Paddington on the night of Sunday 22 December, arriving on the morning of Monday 23 December.

The first sleeper services after Christmas will run on the night of Friday 3 January, arriving on the morning of Saturday 4 January.

The normal Heathrow Express and Elizabeth line services to and from the UK’s busiest airport are also closed. The Piccadilly line on the London Underground will be running.

West Coast Main Line

Closure at Crewe

No trains will run through from one of the UK’s key interchange stations on Friday 27 and Saturday 28 December. After that, services will be below normal levels through to Sunday 5 January, due to resignalling work.

Avanti West Coast services to Preston, Glasgow and Edinburgh will be diverted through the Manchester area, adding significantly to journey times.

On Christmas Eve and Friday 27 December – when large numbers of passengers are likely to be on the move after the two-day shutdown – there will be no Liverpool Lime Street services on Avanti West Coast.

Links from London Euston to Birmingham and Manchester will be reduced from three to two per hour.

On New Year’s Day, the line from Milton Keynes Central to Rugby will be closed. Manchester, Glasgow and Birmingham services will start from Rugby.

Avanti West Coast will run rail-replacement buses between Milton Keynes Central and Rugby.

In addition, Chiltern Railways is running longer and additional trains between London Marylebone and Birmingham Moor Street – a parallel route that is not affected by engineering work.

As a result of engineering works in the Crewe area, there will be no Avanti West Coast services to and from Liverpool.

Christmas Day options

Once again, no trains will run in the UK on 25 December. But FlixBus, Megabus and National Express are expected to run more Christmas Day services than ever before.

In addition, The Independent has learnt British Airways is operating three dozen domestic flights to and from London Heathrow on 25 December 2024 – carrying between them more than 5,000 passengers.

No BA flights will link London with either Inverness or Belfast on Christmas Day; Dublin also has no flights from Heathrow.