THE prospect of the Labour Party changing its position on the potential takeover of Aer Lingus now rests heavily in the hands of the trade union movement.
Several Labour sources admitted last night that the party is being strongly influenced by the stance of Siptu.
The country's biggest trade union has warned of the dangers of selling the State's 25pc stake, but has not closed the door completely.
Labour's opposition to the takeover by IAG has waned among several party members after the airline giant pledged a series of sweeteners on Friday.
Cork TD Michael McCarthy said he now believes the merits of the deal should be examined.
A Labour minister last night said "the door has opened a bit" after promises were made by IAG in relation to jobs and routes.
Siptu, which partly finances Labour, said last night it does not know if there is any possibility of the union supporting the sale.
But several Labour TDs and senators including Joe Costello, Sean Kenny and Lorraine Higgins all said Siptu's stance was vitally important to the party.
If the union shifted its positions and backed the sale of the 25.1pc stake, Labour would likely follow, some sources said.
TDs Michael McNamara, Willie Penrose, John Lyons and Dominic Hannigan, as well as senator Mary Moran, said they are all still opposed to such a deal despite the assurances. The issue is now set to be debated at the Labour national conference in Killarney, Co Kerry, at weekend after an emergency motion was announced by a group of eight party members.
A Labour spokesperson said the party's position has been consistent all along and it will now wait to hear back from IAG.
The British-based airline group offered several concessions surrounding the areas of jobs, passengers and connectivity.
Company boss Willie Walsh pledged to create 635 net jobs by 2020, bring in an additional 2.5 million passengers to Ireland and create five new North American destinations.
In terms of passenger numbers, the revised offer tabled by IAG promises to bring in an extra 2.5 million passengers, of which one million would be long-haul, by 2020.
Such figures, if they materialised, would provide a major boost to the country's tourism sector.
But despite the significant new set of sweeteners, Transport Minister Paschal Donohoe has recommended that the offer be rejected pending more detail and assurances from Mr Walsh.
The stance is being viewed as a gamble within some political circles.
But Mr Donohoe is understood to be open to the idea of a sale if Mr Walsh can come back with an improved offer.