A wave of strikes starting on Tuesday by Tube drivers has been suspended by the Rail, Maritime and Transport union (RMT).
Drivers were due to walk out for 24 hours on Tuesday and Thursday, causing several days of disruption, in a dispute over the voluntary introduction of a four-day week with condensed hours.
On Monday, the RMT said "at the 11th hour the employer has shifted its position allowing us to further explore our members concerns around the imposition of new rosters, fatigue and safety issues".
Transport for London (TfL) described the suspension as "good news for London". Industrial action on 16 and 18 June has been cancelled but fresh strikes have been called for 2 and 4 June.
The RMT has warned that "the dispute is not over and more strike action will follow if we fail to make sufficient progress".
Nick Dent, director of customer operations for London Underground, said: "We are pleased that RMT has withdrawn its planned industrial action this week.
"Our proposal for a voluntary four-day week is designed to improve both work-life balance for drivers and the reliability of service for customers.
"We look forward to further discussions on the implementation of these proposals with all of our trade unions."
No service had been expected on the Circle and Piccadilly lines or parts of the Metropolitan and Central lines.
But many Tube drivers were set to turn up to work as usual, including members of the Aslef train drivers' trade union, which has accepted the proposals, labelling them "exactly the sort of deal every trade union should be trying to achieve".
Aslef has agreed to the voluntary compressed four-day week, saying it gives participating drivers an extra 35 days off a year "in return for some fairly minor changes to working conditions".
The RMT admitted it had "a different perspective from Aslef", branding the voluntary proposals a "fake four-day week that amounts to five days' work compressed into four".
Their concerns include reduced flexibility, shift length and resulting fatigue impacting safety.
Ed Richardson, programme director for transport at BusinessLDN, welcomed the development but said: "Many firms will already have lost out through cancelled bookings and reservations so it's now vital that both sides come to a longer-term resolution.
"With London heading into a busy summer, avoiding further strikes will be vital to help keep the capital's economy moving forward."
