Ryanair is expected to announced later this week details of its plans to list on the London stock market, to add to its existing quotes in Dublin and the US NASDAQ market, writes Cliff Taylor. The move, signalled as in discussion at the airline's publication of its annual results last week, is now believed to be imminent.

Market analysts will pay close attention to how the float in London is structured, as some equity will have to be made available to UK investors. A large issue of new equity is thought unlikely, but Dr Tony Ryan's family, which holds 33 per cent of the shares, may sell some of its holdings.

The other main holders are chief executive Mr Michael O'Leary, who owns 14 per cent, and US investors and Ryanair chairman, Mr David Bonderman, who holds almost 16 per cent.