International infrastructure groups have approached BAA with offers to buy Gatwick, London’s second airport, for up to £3 billion.

Germany’s Hochtief, Global Infrastructure Partners, the GE-Credit Suisse investment fund, Australia’s Macquarie and Britain’s Manchester Airport Group have all indicated their interest to Sir Nigel Rudd, BAA’s chairman. Other bidders, including American and Asian infrastructure funds and Middle Eastern sovereign wealth funds, are expected to emerge in the next few months.

BAA will prepare to put Gatwick up for auction after a ground-breaking report this week from the Competition Commission.

The competition watchdog is expected to say that the group’s ownership of London’s three largest airports - Heathrow, Gatwick and Stansted - is against the public interest. It will be the first time the commission has forced the sale of assets outside a takeover or merger situation.

The sale process could take two years and is expected eventually to yield a healthy profit for the Ferrovial-led consortium that bought BAA two years ago. The Spanish infrastructure group paid £10.3 billion to take BAA off the stock market.

Industry executives who have given evidence to the inquiry believe BAA could even be asked to sell two of the London hubs - Gatwick and Stansted - and one of its largest Scottish airports.

This would end a system of ownership that has held sway for more than 40 years. BAA has owned seven of the UK’s largest airports, including the London trio, since 1965.

Meanwhile, BAA is expected to clinch a crucial and long-delayed refinancing this week. Ferrovial wanted to refinance immediately after the takeover, but was caught by a pricing review and then by the credit crunch.

The Competition Commission may also throw the government’s airport-expansion plans into question by querying its decision not to consider Gatwick as the site for a new runway in southeast England. Gatwick was ruled out in 2003.

A change of ownership at Stansted might put back plans for a new runway there. “A second runway makes no commercial sense regardless of who owns the airport,” said Brian Ross of the campaign group Stop Stansted Expansion. BAA yesterday sold a clutch of airport property interests to the Arora Family Trust for £309m. The portfolio was held by BAA’s joint venture with Morley, the fund manager.

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