Glasgow Airport was today said to be on the brink of a sell-off.

Reports say Spanish infrastructure giant Ferrovial is looking at plans to put the airport on the market this month in a bid to avoid a full-scale break-up of the company being imposed by UK watchdogs.

Any sale would effectively smash Ferrovial's near monopoly in Scotland: the company's subsidiary BAA, the former British Airports Authority, owns Glasgow, Edinburgh and Aberdeen airports and controls more than three-quarters of the Scottish market.

Airlines argue competition between Glasgow and Edinburgh airports could bring down fares and have urged competition authorities to force BAA to sell one or the other.

Earlier this year, the Competition Commission warned the BAA monopoly in both Scotland and the south-east of England may be hurting passengers.

Yesterday, media reports suggested the commission was now sure BAA's control of seven British airports, including London's Gatwick, Stansted and Heathrow, was harmful to the market.

Unnamed legal sources have been cited saying the next round of findings would be an important step towards an order for BAA to sell an airport in Scotland and an airport in England.

Rival airport operators are said to be have been consulted by the commission on what wider ownership would do for the industry.

The commission, however, is not expected to make its full findings public until later this month.

Charlie Gordon, a Glasgow Labour MSP, has been calling for BAA to be broken up in Scotland for years. He said: "I'd love to see some divestment in Scotland."

A spokesman for BAA said it would only make a statement after the commission made its announcement.