British Airways faces its second strike threat in two weeks after 4,500 check-in staff and baggage handlers rejected today the airline's plans for a shake-up of company pensions.

Union leaders at the GMB will hold crisis talks with Willie Walsh, the BA chief executive, on Wednesday in an attempt to thrash out a compromise and avert a walkout.

Ed Blissett, the GMB national negotiator, said: "GMB members covered by the British Airways pension fund have given the union a strong mandate to reject the company's pension funds offer.

"GMB members do not want to cause the travelling public any inconvenience and so they have asked their negotiators to try and negotiate a settlement with BA.

"However, we cannot rule out the possibility of an industrial action ballot sometime in the future if negotiations are unsuccessful."

The GMB is the only union at BA to have rejected the proposals, claiming they disadavantage the airline's lowest-paid staff. A walkout by its members would exert yet more pressure on the airline.

Only a last-minute deal averted a crippling strike by 10,500 cabin crew a fortnight ago.

The strike threat caused thousands of customers to book with BA's rivals. The airline fears that it may have lost as much as £80 million in revenue.

BA is committed to making a one-off £800 million contribution into its pension scheme, along with ten annual "top-ups" of £280 million, in an effort to plug the £2.1 billion hole in the fund.

In return, however, the airline's employees will have to work longer to guarantee the same pension benefits as before.

BA has formally agreed the plans with the pension fund's trustees and unions representing pilots, engineers and the cabin crew staff.

A spokesman said: "At the moment there is no industrial action proposed. Willie Walsh is meeting them on Wednesday and the two sides will discuss a range of issues."

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