Thousands of people making their way home for Christmas face fresh travel woes after the M1 was closed on 24 December following a horrific accident that left two men in critical condition and several others injured.
The incident happened between junctions 12 and 13 at around 2.30am on Christmas Eve. A spokeswoman for Bedfordshire police said two people are thought to have suffered life-threatening injuries in a three-car crash on the motorway between Flitwick/Woburn junctions and the Bedford turn-offs.
Several people were also taken to hospital, while others were treated for less serious injuries, she told BBC News.
Severe delays are expected for travellers heading to London and Luton airport.
A Highways England spokesman said: "A signed diversion route is in place and drivers planning to travel to Luton airport are advised to allow extra time and to plan their journeys.
"Traffic for London is advised to use the A14/A1 and drivers heading towards the Midlands are being advised to use the M40."
The AA estimates that around 12 million people will be travelling on Britain's motorways over the Christmas period.
Network Rail is carrying out 200 sets of engineering works which will affect around 10% of the UK's railways.
Network Rail chief executive Mark Carne told BBC Breakfast they were "making every effort that we can to run the services in the best way that we can.
"The reality is this is the best time of the year for us to do this sort of huge engineering project because the numbers of people travelling by train is about half of what it is on a normal weekend or a normal day. This is the time of year when we can do this sort of work with the minimum effect on the travelling public."
The Southern conductors' strikes will be followed by rail engineering work, set to start on Christmas Eve, Saturday 24 December. Southern Trains have warned passengers that there will be a severely reduced service between 31 December and 2 January due to strike action by RMT conductors.