The UK competition watchdog has ruled that BAA must sell Gatwick, Stansted and Edinburgh airports - a decision that the airport operator will oppose.

BAA is owned by Spanish company Ferrovia and the airline operator currently own seven airports. The final report by the Commission is not due to be published until March, when the airline operator will have the opportunity to appeal.

"We don't want to create a big fuss, but we will use whatever resource is available. If my interpretation of the way the Competition Commission works is correct, we have certain legal mechanisms at our disposal to defend our position," said Joaquin Ayuso, chief executive of Ferrovial.

The Competition Commission are pressing for the biggest change in UK airports since BAA was privatised over 20 years ago, proposing a range of measures including improvements to investment and service levels at Heathrow.

The Commission rejected BAA's argument that the sale of Gatwick airport alone would increase competition sufficiently.