What did the union bosses say?

RMT general secretary Mick Lynch said the action would “close the tube” and “show how important these workers are”.

He said: ‘Transport for London’s (TfL) plans to cut 600 jobs and attack our members’ pensions are simply unacceptable.

“We know that the Mayor of London, Sadiq Khan, has suffered a cut in the TfL budget. However, he must line up with our union and its London Underground staff to push back against the Conservative government, exposing their damaging agenda to a key part of London’s transport infrastructure.

Aslef’s full-time London Underground organizer said the union had joined underground strikes announced by the RMT because changes would make it “impossible” for drivers “to organize their lives outside of work”.

Finn Brennan said: “We only act when needed. Unfortunately, the past few weeks have shown that London Underground management is determined to try and push through damaging changes – despite union opposition – if they think they can get away with it.

“They have already announced that they intend to start training managers in August on a new attendance procedure, and will implement it from January, ignoring the current agreed procedure.

“This new procedure would mean no right of representation or appeal at the first stage of the disciplinary process, and the duration of all warnings would be doubled from 26 to 52 weeks.

“Any illness longer than a week would be considered ‘long-term’, which means a manager can send a driver on redeployment without further meeting. After just six weeks of deployment, a driver can be, as they say, ‘dismissed’.

“Management also wants to impose its plans for what it calls ‘train modernization’. They want unlimited remote bookings, shifts of up to 10 hours, weeks of “flex coverage” in each listing, and fixed ties to be removed.

“It would prevent metro drivers from organizing their life outside of work or having an effective change system.

“Their goal is a fully flexible workforce with all existing agreements replaced – allowing them to cut hundreds more jobs and forcing those of us who remain to work harder for longer. To protect our pensions, working conditions and agreements, our members are ready to act.

How did Transport for London react?

Glynn Barton, TfL’s chief operating officer, said: ‘We are disappointed that the RMT have announced a strike over this range of issues which we have tried to discuss with them openly and cooperatively.

“We urge the union to reconsider and engage with us to discuss the issues and seek a solution.”

The government’s transport agency said there were no current proposals to change its pension schemes, although it is considering a range of proposals to ensure no employee will lose their job or be asked to work overtime.

The RMT said 20,000 railway workers across the UK were also due to strike in July.