TIMELINE - Key dates in the history of Ferrovial's BAA

(Reuters) - Spain's Ferrovial has been ordered by the competition regulator to sell three of its seven British airports within two years, although the operator may appeal the ruling.

Following are some key dates in the history of BAA:

1965 - The state-owned British Airports Authority (BAA) is established to operate airports more flexibly and profitably.

1966 - BAA assumes ownership and responsibility for Heathrow, Gatwick, Stansted and Prestwick airports. Between 1971 and 1975, it acquires Edinburgh, Aberdeen and Glasgow airports.

1986 - The Authority is dissolved and its property, rights and liabilities are passed to a new private company with the same name.

1987 - BAA is floated on the stock market with a capitalisation of 1.23 billion pounds.

1990 - BAA acquires Southampton Airport and Budapest airport in 2005 but sells Prestwick in 1992.

May 2006 - Spanish construction firm Group Ferrovial makes a successful bid of over 10 billion pounds for BAA and officially takes control in June 2006.

May 2007 - BAA sells Budapest airport to German construction company Hochtief for 1.9 billion euros (1.8 billion pounds).