The support of pilots is crucial to a pension settlement

BA's offer to make a one-off �800m payment into the scheme and raise annual contributions to �280m has won support from other unions.

The backing of the British Air Line Pilots Association (Balpa) was crucial to any solution to the huge shortfall.

But the GMB, representing check-in and baggage handlers, rejected the proposed deal and threatened strike action

Separately, the outcome of a strike ballot by 11,000 BA cabin crew will not be known until Monday.

Crunch meeting

Members of the Transport and General Workers Union (T&G) are considering strike action after accusing BA of imposing new rules regarding promotion opportunities and sickness absence.

BA says the proposals will result in more competitive ways of working.

Under BA's offer, its staff can opt to retire at 60 or earlier, rather than at 65, but only if they pay more into the scheme.

Earlier this month, the T&G recommended its members back the BA proposals although they have yet to vote on the deal.

After the GMB turned down the offer, national officer Ed Blissett said: "We are extremely angry and disappointed that the lowest paid workers at BA are being disadvantaged by this final offer in comparison to the highest paid, the pilots."