As soon as this problem arose, we demanded action from Tube Lines and Alstom

A spokesperson for LU said: "London Underground is as frustrated with the suspension of the Northern line as our passengers.

"The situation is intolerable and is bound up in the complex PPP/PFI contracts.

"As soon as this problem arose, we demanded action from Tube Lines and Alstom.

"It is clear that maintenance of the Northern line train fleet was not being done to the correct standards.

"On Friday, after we were provided with just half the Northern line train fleet, we exercised our right to issue an Emergency Direction to Tube Lines, to direct and oversee maintenance.

"This is the first time such action has been taken under PPP.

"We initiated a design review and believe we have developed a modified design for the trip-cock component at the root of this issue.

"We expect the Northern line service to be reinstated as these modifications are completed.

"In the meantime, we will not take action against Northern line drivers who refuse to work on grounds of safety.

"We of course expect them to help to provide information to disrupted passengers, and to move empty trains double staffed to depots, to help us quickly restore the Northern line."

Passenger advice

London Underground also issued the following advice to Northern line passengers:

  • The Northern line will remain suspended for the rest of today and is likely to remain suspended throughout tomorrow
  • Passengers should seek alternative Tube, bus and rail routes. LU tickets will be accepted on all alternative services
  • We are also providing a number of alternative bus services, picking up at station served only by the Northern line, particularly in North London, to link with other Tube lines

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