BAA has decided not to launch a last-ditch challenge to a ruling by the Competition Commission (CC) that compels it to sell London Stansted airport.
The airport operator had previously vowed to take the matter to the Supreme Court, the UK's highest appellate body, after losing its challenge at the Court of Appeal in July.
"Having carefully considered the Court of Appeal's recent ruling, BAA has decided not to appeal to the Supreme Court and is now proceeding with the sale of Stansted Airport," BAA says in statement.
"We still believe that the Competition Commission ruling fails to recognise that Stansted and Heathrow serve different markets."
BAA's capitulation brings to an end a series of legal battles dating back to 2009, when the CC ordered the operator to sell three of its seven UK gateways over fears that it had a stranglehold on airports in Scotland and southeast England.
Global Infrastructure Partners subsequently purchased London Gatwick airport for £1.5 billion in October 2009, and Edinburgh airport for £807 million in April 2012.
BAA had unsuccessfully argued that Stansted is not a direct competitor of Heathrow or Gatwick, as the airport primarily serves low-cost carriers operating leisure flights.
It also voiced concerns that market valuations would be depressed in the current economic climate.
The decision comes less than one week after Qatar's sovereign wealth fund announced the purchase of a 20% stake in BAA. Qatar Holding said it sees value in the "long-term fundamental strength in the British economy".