BAA is furious that it was not consulted over the revision to the national agreement, negotiated last week by the Engineering Construction Industry Association and M&E union Amicus, under which steel erectors at T5 will be eligible for a pay rise.
The union had threatened to ballot over strike action unless an offer of 8% over two years was increased. The unions are now expected to accept an offer of 9%.
We are extremely disappointed by the lack of consultation by the ECIA
The airport operator has requested a meeting with the association over the issue. BAA said: "We are extremely disappointed by the process which was followed and the lack of consultation by the ECIA negotiating body prior to making this revised pay offer to the trade unions."
BAA said the revised offer will be honoured at the T5 site but has made it clear to contractors that BAA will not incur any additional costs.
The statement said: "We were not consulted in the decision to change the offer and we believe that many other clients are in a similar position."
A spokesperson for the ECIA said it had consulted clients, including BAA, more this year than ever before. He said: "You cannot conclude a confidential negotiation successfully by extended committee. There are wide differences of view between the clients, and they have been unable to establish a common or consistent position."
The spokesperson said the association's negotiators had to make a judgment about what was in the best interests of the industry.