Gatwick, Stansted and either Glasgow or Edinburgh airports will have to be sold by BAA under a ruling by the Competition Commission.
The sale should take place in two years, resulting in a break-up of the Spanish-owned airports operator which currently owns seven airports in the UK.
BAA has already put Gatwick up for sale and the Competition Commission wants Stansted sold next followed by one of the two Scottish airports.
The commission stipulated that the airports to be sold should be run by different owners.
The commission said it found competition problems with adverse effects for both airlines and passengers at all of the seven BAA airports in the UK, which also include Heathrow, Southampton and Aberdeen.
The key problem is common ownership "which precludes any competition between them," the commission said.
“There are additional problems at the London airports arising from the current system of regulation, planning and aspects of government policy,” it added.
"The sale of these airports will kick-start a process of competitive rivalry from a standing start where today there is no competition at all."
See separate story for industry reaction.
by Phil Davies
The commission is also recommending that the airports’ regulator the Civil Aviation Authority take “certain specified action” at Heathrow where BAA will continue to have substantial market power even after the sale of Gatwick and Stansted.
BAA airports inquiry chairman Christopher Clarke said: "We are confident the sale of these airports will bring substantial benefits to passengers and airlines.
