Union leaders today stepped up the pressure on airline bosses to try and avert strike action which could cause chaos at Gatwick at the peak of the summer season.

The Transport and General Workers Union will reveal the results of a ballot of 8,000 British Airways check-in and ground staff this week.

The outcome is expected to mirror the results of the GMB ballot, where more than half the members who took part voted to take industrial action.

Unions have rejected a pay offer worth 8.5 per cent over three years.

Their claim, which BA says is the equivalent of 14.5 per cent, will cost £72m over three years.

The T&G calculates the existing BA offer will cost £42m - a difference of £10m a year.

BA's profits have grown by more than half since 2001 and early figures for 2004-05 show total passenger numbers growing at a faster rate than the previous two years.

Brendan Gold, the T&G national secretary for civil aviation, said: "These figures show our members have delivered.

"I think the board should think very carefully now because they have cried wolf once too often.

"They should put some new money on the table. They can afford it."

BA managers have called for more talks to try and stop industrial action and negotiations will be held throughout the week.