Tube closure bombshell

Key sections of the Tube's busiest line could be shut for up to two months at a time.

Plans have been drawn up to close seven sections of the Northern line in turn to carry out repairs.

The line, from Morden in the south to High Barnet and Edgware in the north, carries 650,000 commuters a day.

Urgent large-scale engineering work is required at Bank, Old Street, Camden Town and Kennington making these sections most likely to be shut first.

Closure would be a massive undertaking for London Underground which would have to provide alternative travel, including designated bus services, in heavily-congested areas.

The move was revealed by Tube managing director Tim O'Toole to the London Assembly's transport committee. He said the situation on the City branch is so bad "it is driving us all nuts".

He said the drastic action was needed because night-time engineering work is failing to clear the backlog of vital repairs. Frequent overrunning of night work is also causing huge delays in the day. The most difficult section of the line to close is between Morden and Kennington. Commuters living along that stretch, which includes Balham and Tooting, have no other comparable public transport.

The Northern is the most unreliable line on the network with signal and track breakdowns virtually every day causing huge problems for commuters.

A spokesman for Tube Lines, in charge of maintenance and improvement, said: "We have put in a draft plan to LU for closures of the Northern line." Passenger watchdogs said they would only agree to the plan provided commuters were told months in advance of alternative arrangements and that LU would be able to guarantee that the closed sections would re-open on time.

Cynthia Hay, of Capital Transport, said there was "huge concern" that proper alternative travel arrangements would prove inadequate.

Ken Livingstone has already said that he does not think lines could be closed which serve heavily used shopping areas. However, closing sections at a time could get around the Mayor's fears. The idea is to complete much needed engineering work over a shorter time-scale than confining it to limited periods at night or weekends.

Metronet, in charge of two thirds of the network, is also understood to want to close sections of other lines.