Airport operator BAA could be forced to sell some of its sites following an investigation by a competition watchdog.

The Competition Commission (CC), which is in the midst of a review into the UK’s airport services industry, claims that BAA’s common ownership of seven airports in the UK may not be serving well the interests of either airlines or passengers.

Christopher Clarke, chair of CC’s ongoing inquiry, said: “BAA dominates the airports markets in the south east of England and in lowland Scotland, both areas of high economic activity and importance.

“Currently, there is no competition between BAA’s three London airports (Heathrow, Gatwick and Stansted) and only very limited competition from non-BAA airports such as London City and Luton. Similarly, there is no competition between BAA’s two airports in lowland Scotland (Edinburgh and Glasgow).”

Although the conclusions from the investigation aren’t expected to be made public until August 2008, the CC has hinted that it might require the sale of one or more of BAA’s airports.

According to some analysts, the sale of Gatwick could lead to the new owner reviving plans to build a second runway at the airport, increasing capacity in the region significantly.