EasyJet and Virgin Atlantic are teaming up to back a £2.5 billion bid for Gatwick Airport, The Times has learnt.

The two airlines are talking to financial backers about forming a consortium, with the carriers pledging to base a large number of aircraft at Gatwick to ensure its future income.

Virgin and easyJet would not contribute financially to the bid, but they would guarantee long-term revenue.

BAA, the airports operator, has put Gatwick up for sale to pre-empt a break-up order from the Competition Commission, which is expected to rule next year that the company’s control of London’s airports is monopolistic and bad for passengers.

RBS and HSBC, which are handling the sale of Gatwick, are expected to begin the auction just before Christmas. A prospectus will be made available to interested parties and the price range is expected to be between £2 billion and £2.5 billion.

The companies interested in bidding for Gatwick, the UK’s second-largest airport, are already beginning to form consortiums.

Vancouver Airports, Citigate Infrastructure, which is part of Citigroup, and John Hancock, the US financial services company, have formed one group. The consortium won the licence to operate Chicago’s Midway airport this year and is thought to be an early front-runner for Gatwick.

Hochtief, the German infrastructure company, will also bid and is close to agreeing terms with a financial backer. Manchester Airports Group is attempting to put together a consortium, but is not thought to have secured financing.

Calpers, the California Public Employees’ Retirement System, and Calsters, the California State Teachers’ Retirement System, had talks with a number of the potential bidders without reaching an agreement, and are thought to be looking at backing a buyout by Gatwick executives.

The Competition Commission has said that any bidder for Gatwick must have experience running airports, and so Calpers and Calsters are unlikely to make a bid without the backing of Gatwick’s current management.

The Virgin and easyJet team will bring together the UK’s most successful aviation entrepreneurs, Sir Richard Branson and Sir Stelios Haji-Ioannou, for the first time.

A number of other potential bidders have dropped out because of their inability to access credit or because of a collapse in their existing businesses because of the economic downturn.

Consortiums that join the auction process will be vetted by the Competition Commission to ensure that Gatwick’s new owner will have the financial strength to invest in the airport’s infrastructure. As a result, the process is expected to take some time and may not be concluded until well into 2009. A source said: “This is going to be an orderly process — there’s no reason to rush or be rushed into anything.”

The Competition Commission said in a report earlier this year that BAA, which is owned by Ferrovial, the Spanish infrastructure group, should be forced to sell Stansted and Gatwick to improve competition between London’s airports. Its final report on BAA will be published next year, but BAA is hoping to retain Stansted by voluntarily agreeing to sell Gatwick.

Ferrovial bought BAA for £10 billion two years ago, but has since struggled with the massive debt burden that it took on to complete the acquisition. The Competition Commission does not want the new owner of Gatwick to end up in a similar situation.

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