BA has warned strikes would seriously damage the company

The staff, nearly all based at Heathrow and Gatwick, voted for a walk-out, with a 53% majority - after a 48% turnout.

More than 8,000 Transport and General Workers Union members at six UK airports are also due to vote on strike action before 18 August.

BA warned the strikes by employees would seriously damage the company.

In a personal letter to staff, director of operations Mike Street said industrial action would cause "significant and serious damage" to BA's finances and reputation for customer service.

BA staff in the Amicus union are also involved in the dispute.

This is not a lot of money when you consider that some in the BA boardroom are rubbing their hands over half a million pounds a year GMB chief negotiator Allan Black

The unions have rejected a pay offer worth 8.5% over three years, or 10.5% if the money did not count towards pensions.

They say basic earnings for baggage handlers are about �14,000 a year, while check-in and administration staff, many of whom are women, earn between �2,000 and �3,000 less.

The GMB's chief negotiator Allan Black said: "This is not a lot of money when you consider that some in the BA boardroom are rubbing their hands over half a million pounds a year."

Earlier this week, BA announced increased pre-tax profits of �115m for the three months to June.

The GMB now has three weeks in which it can call a strike, but the union must give seven days notice of any action.

BBC business correspondent Russel Hayes said it was "extremely likely" the union would target the August bank holiday because it was "the busiest time for airports at any stage during the entire year".

Our number one priority is ensuring our customers can continue to look forward to their summer holidays BA director of operations Mike Street

"It would cause utter misery for passengers - there is no question about that," he added.

Mr Black said the union had no wish to disrupt the plans of holidaymakers and other travellers but talks had dragged on for several months.

"We will do everything we can to avoid disruption but management should take note that these low-paid workers are now prepared to take strike action."

If BA had talked to the unions "genuinely and constructively" six months ago, a ballot would not have been necessary, Mr Black added.

"We ask British Airways why is it that talks, begun in the cool of January, have been allowed to drag on into the heat of August and the peak holiday season.

Disrupting travel

"For all this time, as GMB members would expect, we have played hard with BA, but we have always played straight."

Mr Black said he would have liked a bigger majority in favour of industrial action but check-in staff were not militant workers.

"Many of them clearly have reservations about disrupting travel for passengers," he added.

Any strikes would be short stoppages held at key points in the day, Mr Black said.

Protect jobs

Mr Street urged the unions to continue negotiations.

"Our number one priority is ensuring our customers can continue to look forward to their summer holidays," he said.

"Our travelling public do not deserve to be the victims and we will do everything in our power to ensure they are not."

BA's pay offer was "fair and reasonable given the challenges facing our company", Mr Street added.

"We already have the highest employment costs of any airline in Europe and must act responsibly to protect the jobs and futures of all our staff.

Unofficial walkout

"Our staff have performed magnificently in difficult circumstances in recent years.

"I would urge our unions not to unravel that good work by inflicting disruption and inconvenience to our travelling public."

Disruption at Heathrow Airport last summer, when check-in workers staged an unofficial walkout, left 100,000 passengers stranded and cost BA �40m.

That dispute concerned a row over working conditions, including the use of swipe cards to clock in and out of work.