RAIL passengers to London will face hour-long delays over Christmas - despite the efforts of more than 20,000 engineers working on the nation’s rail infrastructure.

Major engineering works planned between East Croydon and Redhill are expected to cause significant delays and line closures.

Network Rail has confirmed that a £150 million programme of works will take place over Christmas and the New Year, despite potential delays and disruptions to tens of thousands of passengers.

The company launched a major advertising campaign yesterday to brief passengers on the more than 500 individual projects which will constitute one of the biggest Christmas upgrades to be undertaken on the railways.

Last year engineering works were delayed, causing widespread disruption.

This time around 20,000 engineers will be deployed, compared with just 12,000 in 2014.

The closure of the Brighton to London main line from December 24 to January 4 will disrupt services to Gatwick and the entire south coast.

Journey times are expected to be increased by more than 60 minutes.

No Thameslink services will run on Christmas Day and Boxing Day.

There will be no Gatwick Express service at all between December 24 and January 4.

Mark Carne, chief executive of Network Rail, said: "Since last Christmas we have received completely reviewed and revised how we plan and manage major upgrades.

"The new measures we have put in place have seen us already deliver over £250 million of improvements over four bank holiday weekends on time.

"Christmas is a quieter time on the railway and our plans will minimise the overall impact of these vital projects on passengers.

"We are continuing to review all the risks associated with our improvement programme this Christmas to make sure that our plans are as robust as possible and we deliver improvements for passengers on time."

These changes to Southern and Gatwick Express services have not yet been incorporated into the online National Rail Enquiries Journey Planner, so passengers should plan journeys carefully and check online for updated information nearer the time.