A 16 inch mains water pipe near Farringdon station first burst at the end of last week, whilst further leaks have resulted in a total of 133 hours of combined delays.
Thames Water stopped the leak from the mains pipe over the weekend but water is still leaking into the tunnel and the rail route between St Pancras and Farringdon will be closed on Wedensday night from 9pm.
Thames Water said it is “doing everything we can to sort out this problem” and that it will continue to work around the clock with Network Rail to try to manage the water levels with pumping equipment.
On the multi-million pound bill the company faces, a statement from the company said: “Our insurers are already involved and we’ll work closely with Network Rail to review what’s happened.”
Thames Water’s head of operational control Chris Featherstone added: “We’re very sorry for the delays commuters have experienced since Friday.
“We know this is a critical job and we’ve got our best teams working as fast as possible to discover where this water is coming from.
“We’re investigating every possibility, including checking all our sewers and water pipes in the area, and we will leave no stone unturned to find out what is happening in that tunnel.”
Phil Verster, route managing director, Network Rail, said: “Passengers have suffered a lot this week as a result of Thames Water’s burst and leaking pipes. We continue to work with Thames Water but the overwhelming extent of the continued flooding made it unsafe to run normal through services between London St Pancras and London Blackfriars since Sunday.
“We have several high output pumps operating but the service is still hugely delayed. We expect Thames water to reimburse passengers, train operators and Network Rail for the significant consequences of these water leaks.”
Stuart Cheshire, Govia Thameslink Railway’s passenger service director for Thameslink, said: “Passengers have been very patient but, like us, that patience has been utterly exhausted. These recurring leaks have to stop.”