The Spanish construction group Ferrovial said Friday it will sell off a further 10-percent stake in British airport operator BAA which controls London\'s Heathrow airport. Ferrovial said in a statement that it will sell 10.62 percent of BAA\'s holding company FGP Topco to the investment fund Qatar Holding for 478 million pounds (607 million euros, $750 million). Ferrovial currently controls just under half of BAA, which runs several British airports and was bought by a consortium including the Spanish firm in 2006. It said other stakeholders in the holding company had sold smaller shares to the Qatar fund, giving it a 20-percent stake in BAA overall and leaving Ferrovial with 39 percent. The total value of these various stakes sold to Qatar amounts to 1.14 billion euros, it said. The latest sale is subject to approval by European competition authorities and is due to be completed this year. Ferrovial aims \"to ensure that Heathrow retains its position as one of the best infrastructure assets in the world,\" Ferrovial chief executive Inigo Meiras said in the statement. \"The transaction further strengthens Ferrovial\'s liquidity situation, providing it with notable flexibility to undertake investments in infrastructure and services projects,\" the statement said. Ferrovial in 2011 sold a 5.88 percent stake in BAA to US investment fund Alinda.