British Airways is to announce the world's largest aviation alliance today, bringing together nine airlines.

The announcement of this alliance will be of major interest to Aer Lingus, as the British Airways-American Alliance alliance is one of the international alliances with which the Irish state airline will have to forge a link. The Government has already decided that Aer Lingus should seek a strategic alliance partner and the search for this partner is now on.

The new alliance, which will be branded Link, will be dominated by British Airways and American Airlines, who will be joined by three major worldwide carriers, Qantas of Australia; Canadian Airlines, which operates out of Vancouver and Cathay Pacific of Hong Kong.

A spokesman for BA refused to give further details but confirmed that Mr Bob Ayling, chief executive of BA and his American Airlines counterpart, Mr Don Carty would be unveiling a "major worldwide airline initiative" today. Regulators are already scrutinising a transatlantic alliance between BA and American.

Other airlines thought to be included in the Link alliance are Japan Airlines, Iberia of Spain, Maersk Air of Denmark, GB Airways in the UK, American West and Finn Air.

A spokesman for British Airways said the alliance with American Airlines had to be "good news for the consumers". He indicated that a wider alliance would enhance service for BA passengers, enabling the company to offer a "one stop shop" for airline travellers that - offers a greater choice of destinations and more flexibility with booking times.

He added: "Any alliance would be in competitive response to other similar arrangement already in place." This refers to the Star Alliance, which was able to begin building a global network while BA and American were caught up in the regulatory process.

The Star Alliance involves US carrier United Airlines, Lufthansa from Germany as well as airlines in Canada, Scandinavia, Thailand and Brazil, and is also a potential strategic partner for Aer Lingus.

Rival airlines, who have already criticised the BA/American alliance claimed this larger venture would be detrimental for consumers.

The European Commission produced a draft analysis of the BA/American alliance six weeks ago, and the matter is still under consideration.

If the regulators gave the green light to this alliance, it is not thought that it could be launched until at least next year.

Currently the UK's Department of Trade and Industry (DTI) is asking BA and American to give up a certain number of "slots" on transatlantic routes if the merger goes ahead.

But heated debate surrounds the number of slots that should be sacrificed. If the global alliance is proposed, then it is likely that both BA and American would have to give more slots to competitors, opening some of these routes up to competition.