The Competition Appeal Tribunal (CAT) has ruled BAA may maintain its present position in the UK market, quashing an earlier decision by the Competition Commission.

The commission had ruled, in view of BAA “virtually monopolistic” control of the UK’s airports, the organisation should be forced to sell Gatwick and Stansted Airports, along with either Glasgow or Edinburgh Airport.

While Gatwick has already been sold – as part of a £1.51 billion deal with Infrastructure Partners (GIP) late last year – the CAT decision means BAA will now be able to keep Stansted, Glasgow and Edinburgh Airports. 

BAA – which is owned by a consortium led by Grupo Ferrovial - also operates London’s Heathrow Airport, Southampton Airport and Aberdeen Airport.

The CAT decision will see the matter referred back to the Competition Commission for reconsideration. However, this referral will not take effect until the conclusion of any appeal.

The Competition Appeal Tribunal also decided the Competition Commission’s and Ryanair’s requests for permission to appeal be refused. However, the Competition Commission still has an opportunity to seek permission to appeal directly from the Court of Appeal.

Ryanair, an ardent supporter of BAA’s break up, instantly condemned the decision.

“Today’s decision, which appears to be based on a legal technicality (or irrelevancy), will now delay the much needed introduction of competition and consumer choice at Stansted by at least two years,” said Ryanair’s chief Michael O’Leary.

“We regret passengers at Stansted will pay higher charges and suffer inferior facilities for at least two more years as a result of this regrettable Competition Appeal Tribunal decision.”

BAA was also able to win an initial appeal to the CAT in December 2009 after complaining of an “apparent bias” at the Competition Commission.

Professor Peter Moizer - a member of the panel that ordered its break-up - was also an adviser to a pension fund linked to Manchester Airport Group, a potential buyer of its airports.

The latest decision raises questions over procedure at the Competition Commission, which has also seen key decisions at over the future of Tesco and Barclays reversed in recent months.