British Airways risks a serious escalation of its dispute with cabin crew after the Unite union warned it would consult 30,000 members across the airline on action.

Unite joint general secretary Tony Woodley said: “This is no longer a matter for BA cabin crew alone.”

The union plans meetings with representatives of check-in workers and baggage handlers, which could lead to more serious stoppages than the airline has suffered so far this year.

BA and Unite negotiators are due to meet again for talks this week in Manchester, where the TUC trade union federation is holding its annual conference. But the talks may be soured by news that BA has asked call centre staff to collate passenger reports of “inappropriate comments” by cabin crew.

Disciplinary action by BA against more than 80 staff and the withdrawal of travel concessions to strikers remain the issues preventing a settlement of the year-long dispute.

Woodley warned the union was engaged in a struggle to defend trade unionism at BA, saying: “It is now clear agreed procedures are being abused for purposes of trying to destroy trade unionism among cabin crew.”

He said: “It was my view from the start that this, not cost reductions, was BA’s real agenda.”

Woodley will tell other BA workers: “If trade unionism is smashed among cabin crew, these methods will be extended to other groups of unionised BA employees.”

The move is significant as BA has relied on other sections of the workforce to carry on working and do the job of cabin crew during 22 days of strikes in March, May and June.

However, Woodley continued to downplay any immediate move to a fresh strike ballot. A spokesman for BA said: “We remain committed to working with our trade unions and have agreed [recent] deals with Unite.”