British Airways' cabin crew, who are threatening industrial action over new working practices proposed by the company, have vowed not to go on strike over the Easter holidays.

The announcement by Unite comes after a judge ruled that its planned 12-day Christmas walkout was unlawful after the union balloted staff that planned to leave the UK flag carrier. A fresh vote will take place next Monday.

"It was never the intention of Unite and its BA cabin crew membership to call industrial action over Easter," said Len McCluskey, Unite's assistant general secretary.

"I want to make it abundantly clear that, if industrial action receives the required mandate from the members and strike action is made necessary by continuing management intransigence, we will not call such action over the Easter holiday period. We are making this announcement now so families can plan their travel arrangements with confidence."

Mr McCluskey added that Unite was still hoping negotiations with BA could resolve the dispute, which centres on the group's plans to cut at least one flight attendant from long-haul flights from Heathrow. The last round of talks ended without agreement on 15 January with Unite laying the blame for the dispute at the door of BA.

"It remains our hope that this dispute can be resolved through negotiation, without the need for strikes at any time at all," said Mr McCluskey. "But this can only happen is BA management wake up and realise that treating their greatest asset – skilled and professional employees – as enemies is the road to ruin. You can't fly planes on management machismo."

British Airways' chief executive Willie Walsh has said that staff from elsewhere in the company will be trained as cabin crew to avert the threat of grounding planes.

"According to Unite's ballot timetable, it is threatening the travel plans of families and business people from 1 March," a spokeswoman for BA said yesterday. "Assurances about an unspecified Easter holiday period will be of little comfort to them."