In one of the largest majorities seen in such a dispute, some 96 percent of cabin crews voting on the action opted for a strike, the Transport and General Workers Union said. No strike deadline was set.

Cabin crew workers had claimed the airline pressured them to come to work even if they felt sick, the union said. A separate dispute focused on pension plans.

British Airways officials issued a statement to decry what they described as an unnecessary strike.

"We have not been seeking to achieve new ways of working by imposition, but by negotiation as in many other areas of our business," the airline's statement said.

"The leaders of the (union's) cabin crew branch have created a worrying time for our customers and our staff."