Tube passengers are being warned to expect delays over the next year as London Underground (LU) begins £5bn of improvements to the network.
LU is investing £5bn in transforming the network
Transport for London (TfL) has announced a major increase in work this year and has warned of disruption.
This includes weekend closures, throughout 2006, on the Northern Line and the closure of the Waterloo & City for five months from 1 April.
TfL urged passengers to check before they make a journey.
LU Managing Director Tim O'Toole said: "We're investing billions and working hard to deliver a safe, reliable and clean Tube service, every day.
PLANNED TUBE WORKS
On the Bakerloo Line, Regent's Park Station will be closed for about a year from July 2006
On the Central Line, a series of 15 weekend closures from April
The Circle, District and Hammersmith & City lines will be partly suspended on about six weekends in the central London area between November 2006 - March 2007
On the Northern Line, a major series of weekend closures, throughout 2006, from April
On the Piccadilly Line, three further Acton Town to Uxbridge closures from May 2006 and further Cockfosters to Wood Green / Arnos Grove closures
On the Victoria Line, Brixton station will be closed and the line will terminate at Stockwell over Easter from 8 to 17 April 2006
The Waterloo & City Line will close for five months from 1 April.
"But in order to transform the Tube, we need to step up the amount of work being done at weekends and this will mean some disruption for passengers.
"We will be working hard to provide information and alternative travel options to keep Londoners, visitors and Tube users moving."
About 50 stations will have improvement works over the coming year.
These include Baker Street, Embankment, King's Cross, St Pancras, Farringdon, Blackfriars, Earl's Court, Bethnal Green and Mile End, which will be modernised.
In addition, Network Rail, Channel Tunnel Rail Link and the new White City development will also mean the suspension of parts of Underground lines.
Commenting on the work Roger Evans, Chairman of the London Assembly Transport Committee, said: "Tube passengers know better than anyone that the standard of service for millions of journeys is unacceptable.
"There is an impatience for change on the Underground. Line closures can only be justified if they dramatically speed up improvements."