The RMT union has extended its strike mandate on the London Underground for a further six months, raising the possibility of further disruption.
Tube workers voted to continue the campaign in a long-running dispute over jobs, conditions, and pensions.
The RMT said 95% of its members voted in favour of continuing strikes on a 54% turnout.
RMT general secretary Mick Lynch said: "I congratulate our members on delivering another impressive ‘yes' vote in our campaign on pensions, jobs and working conditions on London Underground.
"Our union will now consider the results and the next steps in this campaign."
The move has prompted fears strikes could disrupt hospitality's ‘golden quarter' during the festive season, which can help sustain businesses through the quieter months of the new year.
It comes after the RMT this week said it had reached a possible breakthrough with mainline rail operators that could bring an end to disruption on the railways.
Both parties have reached a Memorandum of Understanding which, if RMT members agree, will pause industrial action through Christmas and into spring as negotiations continue.
In October, 37 hospitality brands, including Wasabi, Greene King and Rosa's Thai, signed an open letter in partnership with UKHospitality urging rail unions not to strike during the festive period.
The managing director of Dishoom said he was fearful the group could lose 3,500 bookings over Christmas if there were further train strikes during the festive period.