History suggests that International Airlines Group chief Willie Walsh, pictured, does not hang around. So a revised offer for Aer Lingus can be expected to emerge shortly. The former Aer Lingus boss will know he faces a complex battle where price is only one factor in the equation.

IAG approached the Aer Lingus board in mid-December and is believed to have offered around €2.20 a share. This was rejected by the board as “fundamentally undervaluing” the airline. Since then the market has been anticipating a return from IAG, with the shares trading yesterday at €2.20 – well above the €1.40 to €1.60 range at which they spent the bulk of 2014.

There has been speculation in London that IAG is preparing to up its bid to more than €2.40, which would be more than a full euro above what Ryanair offered in its last 2012 bid. Ryanair and the Government might well be financially attracted by such an offer, but both are likely to be more motivated by other agendas.

The Government, which owns 25.1 per cent of Aer Lingus, will want the key Heathrow slots owned by Aer Lingus to continue to be used for traffic from Ireland – not only Dublin but also the regional airports. IAG might well want to move some of them to lucrative long-haul traffic. Meanwhile Ministers will also want an IAG-owned Aer Lingus to continue direct flights from Ireland to North America, seen as vital for foreign direct investment and tourism.

Ryanair’s attitude will be driven by its view of what kind of competitor an IAG-owned Aer Lingus would be. Michael O’Leary will know that the UK court of appeal is most likely to rule shortly that Ryanair must abide by a UK competition ruling to sell down its existing 29.8 per cent share to, at most, 5 per cent. If O’Leary is resigned to selling his Aer Lingus stake, the calculation will be whether anything is to be gained by hanging on. Walsh is due in Dublin to speak at a business conference tomorrow. He should not expect to have a quiet day.