The RMT union is planning to ballot 6,500 staff over a pay dispute. Members could vote for a tube drivers strike, meaning travel misery for millions of Londoners.

There will be a separate strike vote by 80 staff at Canary Wharf station, after union claims of harassment and victimisation against gay and female members of staff.

RMT general secretary Bob Crow said today: “The Canary Wharf group is supposed to be LUL’s showpiece station group, but managers there are running out of control to the extent that industrial relations have now entirely broken down.

“A female member of staff who was sexually assaulted on the barrier has suffered constant harassment from local management since.

“A gay member of staff has suffered homophobic remarks, and there is a widespread view that gay staff members are routinely discriminated against.”

A London Underground spokesman told PinkNews.co.uk : “London Underground has a strong policy against harassment of any kind and takes such matters extremely seriously.

“In this case, the RMT’s claims have already been subject to formal investigation and were not founded. If there are further issues then balloting for strike action as a first step is not the way to resolve any issue.”