A Spanish infrastructure company today said it was planning a possible takeover of BAA - the owner of seven UK airports, including Heathrow.
Grupo Ferrovial, which owns construction company Amey, said no approach had yet been made, but that any offer was likely to be as part of a consortium.
BAA shares jumped by as much as 20% following the surprise statement from Ferrovial, which already has a 50% stake in Bristol airport and complete ownership of Belfast City airport.
The UK company, which is valued at more than £8 billion based on today's share price rise, also owns and operates Gatwick, Stansted, Edinburgh, Glasgow, Aberdeen and Southampton airports.
Ferrovial issued its statement in response to recent movements in the BAA share price.
It said: "Ferrovial's considerations are at a preliminary stage and there is no certainty that any offer will be made. No approach has yet been made to the board of BAA."
The company is one of Europe's leading construction, services and infrastructure groups, with more than 68,000 employees and a presence in 40 countries. It has annual revenues of more than seven billion euros (£4.8bn).
Keith Bowman, equity analyst at Hargreaves Lansdown Stockbrokers, said the offer had come as "a complete surprise".
He added: "There is likely to be much deliberation over such a bid and it is almost unthinkable that the UK Government would not become involved.
"What the potential bid does again reaffirm is the significance of so called 'strategic assets' as with the current bids for the London Stock Exchange and P&O ports."Reuse content