RMT members on the Tube are locked in a bitter dispute with Transport for London over pay, jobs and pensions.
In a statement on Tuesday, the union said continuing strike action was backed by 96% of members who voted. The turnout of 56.5%.
RMT general secretary Mick Lynch said: “I congratulate every single one of our London Underground members for giving us continued industrial leverage at the negotiating table.
“TfL cannot continue to simply wish this dispute away and the government which has drastically cut the funding to London transport budgets, shares a great deal of responsibility for this continuing impasse.
“London Underground workers want a negotiated settlement and are quite prepared to take more strike action over the next six months to make that a reality.”
No new dates have been set yet but could be announced shortly. This would see the RMT’s 10,000 Tube members walk out and force much of the Underground to close.
The union is in a long-running dispute with Transport for London over the perceived threat to TfL staff pensions.
This has already resulted in six RMT strikes last year and the shutdown of the Tube on March 15 Budget Day this year, when Tube drivers belonging to Aslef also walked out.
Glynn Barton, Transport for London’s Chief Operating Officer, said: “We were notified today that RMT members have voted to renew their mandate for industrial action over jobs, pensions and conditions.
“This is despite the fact that no proposals have been tabled on pensions following a Government mandated review into the TfL pension scheme. If any proposal is made in the future, this would require appropriate consultation and extensive further work.”
The RMT has also been angered by the removal of up to 600 station staff posts, which it says leaves some stations unmanned at times or staff working in isolation.
TfL insists that no proposals to change the staff pension scheme have been tabled.
It is deadlocked in a row with the Department for Transport over Government wishes for savings to be made to the pension scheme.
TfL say the demands for cuts – a condition of TfL’s covid bailouts – are no longer relevant as the pension scheme is now in profit.
The RMT claims that some workers could lose more than 30 per cent of their pension.
TfL wrote to the Government in March to say it was “not possible to progress” any changes to the pension scheme. The transport body says that “no changes to the TfL pension are currently being proposed”.
It came after members of the TSSA union cancelled a planned 24-hour walkout on the Elizabeth line on Wednesday that would have brought its central section, between Paddington and Abbey Wood, to a standstill.
Some 80 per cent of line managers belonging to the TSSA voted to accept an improved pay offer. The action had been threatened in a bid to secure pay parity with workers in similar jobs employed by other TfL contractors.
TSSA interim organising director Mel Taylor said, “Elizabeth Line’s new offer recognizes the uniquely multi-skilled nature of our members, who operate the world’s only fully digital railway.
“Our members were being paid thousands of pounds less than colleagues performing similar roles on other parts of the Transport for London network. This offer goes some way towards bringing their pay more in line with the rest of TfL. The revised offer from Elizabeth Line rewards the multi-skilled role and offers staff an opportunity for career progression.”
In January the dispute saw a one-day stoppage – the first on the Elizabeth line - by dozens of TSSA members, which closed the central section of the line.
Meanwhile National Rail strikes will resume at the end of the month, with drivers’ union Aslef walking out on Wednesday, May 31, and Saturday, June 3, and RMT members striking on Friday, June 2.
It means travel will be significantly disrupted on FA Cup Final weekend, when Manchester City and Manchester United are set to meet at Wembley.
The Government is pressing ahead with legislation aimed at providing minimum levels of service during strikes.
There was a protest outside Parliament on Monday evening when the Bill was voted through by MPs.
It will be debated in the Lords again before becoming law in the next few weeks.