Major sections of the regions rail network will be shut down yet again between Christmas and the New Year, it was revealed today.
It means travel chaos for hundreds of thousands of passengers and families visiting relatives.
Southeastern, First Capital Connect (Thameslink) and Southern services using London Bridge will be among those worst hit.
There will also be major disruption on the Brighton line.
Journeys between London and the north will be severely restricted with no direct services on the busy West Coast Main Line (WCML) from Euston to Milton Keynes, Manchester, Liverpool and Glasgow on Sunday 23 December and Monday 24 December.
During the shutdown services will be restricted to just one train an hour to the north from Euston via an alternative (Chilterns) route to Nuneaton where passengers will change to continue their journeys, adding more than an hour.
Direct services resume on Thursday, 27 December, but only two of the usual four lines will be open up to and including Thursday, 31 December meaning many cancellations.
Network Rail (NR) said it "regrets the impact" this will have on passengers but the line must be closed for major engineering work.
All train operators are expected to be told later this week the full extent of the line closures.
A senior industry source said: "It is going to be bad, there will be a lot of closures.
"Anyone travelling over the Christmas and New Year period will have to check well in advance to make sure their train is running."