The government's battered and bruised airport expansion policy was dealt yet another blow after BAA yesterday confirmed it is to appeal the Competition Commission ruling that it must sell off three of its airports – a move that is likely to further delay the planning inquiry into proposals for a second runway at Stansted.

A spokesman for BAA confirmed that the airport operator had written to communities and local government secretary Hazel Blears to inform her that it would be appealing against the Commission's decision instructing it to sell Gatwick, Stansted and one of its Scottish airports, and, as such, there uncertainty remains over the future ownership of Stansted.

Blears had announced earlier this year that she was to delay the planning inquiry into the proposed expansion at Stansted until after the Competition Commission had ruled on BAA's ownership of the airport.

The BAA spokesman said that it was up to the minister to decide whether to delay the inquiry further, adding that the company was ready to take part in the inquiry if it was given the go ahead. But he added that Blears had said the reason for the delay was to achieve clarity over the ownership of Stansted and the decision to appeal the Commission ruling means that has not yet been achieved.

With the planning inquiry expected to take between a year and 18 months, it is now inconceivable that a decision will be reached before the next election. With the Conservatives riding high in the polls and committed to blocking expansion at Stansted, Heathrow and Gatwick it appears that the chances of BAA's building programme being realised are receding fast.

The company has already announced it is to delay its building plans for Stansted by two years to 2017, as a result of lower than expected passenger numbers.