Replacing Mr Michael Foley as chief executive at Aer Lingus is not going to be easy. His successor will join an airline facing significant trading difficulties and which may yet be sold by the Government. The new chief executive will also inherit a difficult relationship with trade unions at the airline, whose rivalry over the representation of cabin crew has been bitter.

If Aer Lingus opted to hire an external candidate, the process could take some time. When the previous chief executive, Mr Garry Cullen, resigned in February 2000, the State airline took six months to appoint Mr Foley.

Less time would be required to promote an internal candidate. For this reason, and because an Aer Lingus insider would have knowledge of the company and its many problems, that approach may be favoured by senior figures within the airline.

However, it is thought the company was keen to recruit a heavy-hitter from the private sector when Mr Foley was headhunted. He received a salary of about £250,000 (€317,430); Mr Cullen was believed to earn about £100,000.

At the time of Mr Foley's appointment, Aer Lingus was preparing for a stock market flotation, though the Government's advisers have since been told to take soundings on the possibility of a trade sale.

Whether the company will headhunt another external candidate or whether some of those interviewed for the position last year will be approached again remains to be seen. Either way, the position demands managerial flair and considerable political nous.

Among those seen as a likely internal candidate is the company's finance director, Mr John O'Donovan, who was appointed in 1995 and joined its board last July. While Mr O'Donovan played a key role in the company's recovery from a grave financial crisis in the mid-1990s, he is known not to have applied for the position of chief executive last year when it became vacant.

The airline's chief operations officer, Mr Willie Walsh, and its commercial director, Mr Mark Mortell, are also seen as potential candidates.

The airline's deputy chief executive, Mr Larry Stanley, also did not apply for the position of chief executive last year. Neither did he apply when Mr Cullen's predecessor, Mr Gary McGann, left the airline. He is again considered unlikely to apply on this occasion.

Mr Stanley was acting chief executive while the process of appointing Mr Cullen and Mr Foley took place. He has not taken that role on this occasion. Instead, Aer Lingus chairman, Mr Bernie Cahill, is acting as executive chairman.

The board of the company is expected to meet soon to initiate the recruitment process. Its most likely approach will be to appoint a subcommittee to make the appointment, as happened last year.

The subcommittee which hired Mr Foley was chaired by Mr Cahill. Its other members were Mr Des Richardson and Mr Paddy Wright, who, ironically, were members of the subcommittee which sacked Mr Foley yesterday. Mr Foley was first approached last year by a recruitment consulting firm, Barry Herriott Search & Selection, acting for Aer Lingus.

Then working as president and chief executive of Heineken USA, Mr Foley was already known to Mr Cahill. He had worked until 1994 as managing director of Murphy Brewery Ireland, owned by Heineken Corporation, of which Mr Cahill was a director.