PASSENGERS using Southampton Airport could be hit after firefighters and security staff threatened to strike over pay.

Thousands of workers at seven airports, including Southampton, Heathrow and Gatwick, voted to take industrial action, which could involve one-day stoppages from later this month.

Pilots' leaders warned that the situation was "very serious" and could lead to the closure of airports.

Thousands of workers employed by the British Airports Authority voted in favour of walkouts to protest against a pay offer, which the employers said was worth 6.3 per cent over two years.

The Transport and General Workers Union and Amicus said the decision of their members showed the "sheer frustration" of workers at the company's offer.

Workers involved in the row include firefighters, security guards and support staff at seven airports - Heathrow, Gatwick, Stansted, Southampton, Aber-deen, Glasgow and Edinburgh.

Tim Lyle, the TGWU's national secretary for aviation, said workloads had increased at airports since the September 11 terrorist outrage.

"Coupled with the knowledge that traffic figures have improved and the company is in profit, our members justifiably feel that the pay offer falls short of what they deserve."

Union officials will meet on Monday to plan the industrial action, which could involve a series of 24-hour strikes. The airport firefighters are not involved in the national firefighters' dispute and were expected to work normally in the event of any industrial action called by the FBU.

The TGWU said the rejected offer was worth 1.7 per cent from last April, plus £150, then a further £150 from next January followed by an increase of the rate of inflation plus one per cent from April 2003.

A spokeswoman for BAA said: "We have good relations with our unions and workforce and despite having reached agreement with the trade union representatives over this year's pay review, two of the unions' (TGWU and Amicus) membership have voted to reject the offer.

"We will be holding further discussions to understand and resolve the issue."