Airport operator BAA was today told it must still sell either Edinburgh or Glasgow airport.
In a provisional ruling, the Competition Commission said it saw no reason to change its 2009 decision that the company had to dispose of both Gatwick and Stansted airports and either Edinburgh or Glasgow.
BAA has battled through the courts to overturn the original decision, but the legal challenges ended with the commission's findings being upheld.
BAA has already sold Gatwick and today the commission provisionally concluded that the sale of the other airports should also go ahead.
The commission said it remained convinced the original sale decision was "the right one for passengers and airlines". It added that Stansted should be sold first, with a "small overlap" between that sale and the sale of either Edinburgh or Glasgow.
BAA said today: "We believe that there has been a material change in circumstances since the commission's report was published in March 2009."
The commission will now invite responses to its provisional decision before publishing a final verdict in May or June.
BAA also operates Heathrow, Southampton and Aberdeen airports. It had already decided to sell Gatwick before the 2009 ruling and it was sold for 1.5 billion in 2009.
Commission chairman Peter Freeman said today: "We remain convinced that the original decision to require BAA to divest three airports is the right one for passengers and airlines.
"We have re-examined that decision in the light of a significant subsequent development when the Government decided to rule out further runways at London's airports. We are clear that many benefits will still arise without that expansion, by addressing detrimental effects from BAA's common ownership."
He added that there had been "no cause to alter our view on the need for either Edinburgh or Glasgow to be under separate ownership".
Making its ruling in 2009, the commission said it had found that at its south east England airport, BAA had shown "a lack of responsiveness to the interests of airlines and passengers".
The commission also said common ownership "adversely affects competition between Edinburgh and Glasgow".
n THE failure to keep Edinburgh airport open during last year's snow has deterred financial companies investing in the city, according to accountants PwC.
A report, based on a survey of chief executives in the financial sector, warned the Capital was slipping down the international league of financial centres. It singled out the airport closure as a symbol of other problems. But it said employment in the sector could double by 2020 if infrastructure issues are tackled.