BAA Ltd., the owner of Heathrow airport, must sell another London airport and one in Scotland to promote greater competition, Britain's anti-monopoly agency said Wednesday.
In a preliminary ruling upholding a decision two years ago, the Competition Commission said it believed passengers and airlines would benefit if BAA sold London Stansted and either one of its Edinburgh or Glasgow facilities.
"The introduction of new ownership at Gatwick, whilst too recent for us to base any conclusions on, has also given a foretaste of the benefits competition can bring," said Peter Freeman, chairman of the Competition Commission. "There has also been no cause to alter our view on the need for either Edinburgh or Glasgow to be under separate ownership."
The commission said it planned to make a final ruling in May or June.
BAA, which had already been forced to sell London Gatwick airport two years ago, said it believed conditions had changed since 2009 but gave no indication whether it would appeal.
The big change since 2009 is that Prime Minister David Cameron's government has canceled plans for building additional runways at Stansted and Heathrow.
BAA, which took over airports formerly owned by the government in 1986, has been owned by a consortium led by Grupo Ferrovial SA of Spain since 2006.
BAA had appealed against the 2009 decision on grounds of apparent bias but lost. In February, the Supreme Court refused to allow BAA to make further appeals in British courts.
The company could still seek to take the case to the European Court.
Global Infrastructure Partners, which also owns London City airport, paid 1.5 billion pounds ($2.4 billion) for Gatwick.