Members of the Aslef and RMT unions were due to stage walkouts next week, threatening major disruption for millions of commuters.

The industrial action was called off after talks with Transport for London (TfL) at the conciliation service Acas.

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Aslef's Finn Brennan said: "After a week of intense negotiations, we have made real progress in making sure our members' working conditions and pensions are protected."

RMT general secretary Mick Lynch said: "There has been significant progress made by our negotiating team.

"However, this is not the end of the dispute nor is it a victory for the union as yet.

"Our members were prepared to engage in significant disruptive industrial action and I commend their resolve.

"RMT's strike mandate remains live until October and we are prepared to use it if necessary."

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Mr Lynch added that, in his view, only the threat of strikes led to progress in talks with TfL.

He said: "We will continue to negotiate in good faith as we always have done with TfL and it was only the steadfast commitment of our members in being prepared to take sustained strike action that has forced the employer to make significant concessions.

"Our campaign to defend jobs, conditions and our members' pensions will continue in the coming weeks and months."

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Welcoming the development, London Mayor Sadiq Khan said: "Despite the onerous funding deal conditions imposed by the government, we have managed to avoid industrial action.

"Negotiation is always the best way forward and this shows what we can achieve by working with trade unions."