Strikes by tube staff are due to start on Friday, in a series of walkouts that are expected to close the London Underground entirely for four days from Monday.
Londoners have been urged to check before travel next week, with almost no tube services expected to run and other transport in the capital likely to be affected by crowding and congestion.
The Elizabeth line, London Overground and national rail services will continue to run, as will London buses.
The Docklands Light Railway will also be closed on Tuesday and Thursday, in a separate dispute.
The RMT union has called out all its tube members, just over 10,000 of London Underground’s 15,000 staff, to strike in the dispute about working hours and conditions in pay talks.
No further talks between Transport for London (TfL) and the RMT are expected to take place, with TfL now viewing as inevitable the first significant strike under the leadership of Eddie Dempsey, who took over as general secretary from Mick Lynch this year.
TfL said it would operate as many services as possible. It said it had made a “fair, affordable pay offer” of 3.4%, in line with RPI inflation and other pay deals agreed in the rail industry with the union, but could not budge on a central union demand to reduce the working week from 35 to 32 hours.
The strike ballot is understood to have taken place before the pay offer, with a turnout of 57% of RMT members.
Aslef, which represents about two-thirds of tube drivers, is yet to accept a deal but its members are not expected to strike.
The series of RMT strikes begins with depot managers at Ruislip, west London, but services are not expected to be affected until Sunday, when action by power and track access controllers will cause limited disruption.
Staff working on trains and stations will strike on Monday and Wednesday, and signallers and service controllers will take action on Tuesday and Thursday.
The action is likely to mean virtually no tube trains running from early evening on Sunday 7 September until 8am on Friday 12 September, according to TfL.
The RMT said TfL management had “refused to engage seriously with union demands on pay, fatigue management, extreme shift patterns and a reduction in the working week”.
Dempsey said tube staff worked “strenuous shift patterns” that were “impacting on our members’ health and wellbeing”.
Claire Mann, the TfL chief operating officer, said: “We call on the RMT to suspend this action, put our fair and affordable offer to their members and continue discussions with us. Our pay deal is in line with other offers accepted by the RMT across the rail industry, so it is disappointing the RMT is planning to disrupt Londoners without giving their members a say on the offer.
“We remain open for discussions about any part of our offer, and we are committed to making sure our colleagues are treated fairly. We welcome further engagement from all of our unions about managing fatigue across the network, but a reduction in the contractual 35-hour working week is neither practical nor affordable.”
Train operators, or drivers, earn an average of £71,000 and station staff earn £44,000. Some striking service controllers are understood to earn more than £100,000 a year.
The RMT is understood to be also seeking an extension of perks including heavily subsidised national rail travel.
A planned tube strike at the start of 2024 was called off after the London mayor, Sadiq Khan, surprised TfL negotiators by announcing an extra £30m to fund pay increases, a move seen by some as fuelling threats of more industrial action this year.
Meanwhile, the train drivers’ union Aslef has announced industrial action at the national operator CrossCountry, including a strike on 3 October. The union is continuing its dispute at Hull Trains over a sacked driver, after holding a protest rally in the city last week.
