Customer service managers on London Underground are to stage a fresh strike in a dispute over terms and conditions.
Members of the Transport Salaried Staffs’ Association (TSSA) will walk out on Friday and ban overtime until 5 May.
The union said the action could cause tube stations to close at the last minute, including into Saturday morning. The workers held a previous strike earlier this month.
The TSSA’s general secretary, Maryam Eslamdoust, said: “It’s clear that our customer service managers’ strike on 10 April made a real impact, many stations shut at short notice, and we had overwhelming support from the public.
“Because of London Underground’s refusal to get back round the negotiating table, we have been forced to take further strike action this week.
“London Underground must now come clean with the public. Their refusal to negotiate seriously and fairly with our union will lead to stations closing at the last minute and other stations being understaffed.
“We have made it clear that our union will not accept the continued threats to our members’ roles, locations, terms and conditions to stand unchallenged.
“We will continue to take sustained action until London Underground is prepared to negotiate with us in good faith.”