Tube workers on the Piccadilly Line could strike after they accused Travel for London (TfL) of developing a "campaign of bullying, harassment and intimidation".
Walkouts were backed by 70 per cent of the line's Rail, Maritime and Transport (RMT) union members.
Mike Cash, the general secretary of RMT, said: "The wholesle abuse of procedures and agreements by management on the Piccadilly Line is rife and amounts to the development of a campaign of bullying, harrassment and intimidation that the union will not allow to continue and the anger on the shop floor is reflected in these massive votes for action."
Mr Cash continued: "The combined weight of these issues has built up to a comprehensive and fundamental collapse in industrial relations that the company have done nothing to address leaving RMT with no option but to ballot for both strike action and action short of strike."
"The executive will now consider the mandate we have for action," he said, adding that the union remained "available for talks".
Pat Hansberry, Operations Director for London Underground, said in a statement: “This vote for strike action is completely unnecessary. We urge the RMT union leadership and members to work with us constructively on the issues they have raised rather than threaten to needlessly disrupt our customers with possible strike action.”
The Piccadilly Line is the London Underground's fourth busiest line and transports around 600,000 passengers a day.
