BAA also has interests in the US, Italy and Hungary

Spanish construction group Ferrovial currently has the airports group in its sights, but BAA has rebuffed its �8.75bn offer as too low.

The Sunday Telegraph said the group would reveal its payout to investors in a defence document later this week.

BAA - which operates seven UK airports including London's Heathrow, Gatwick and Stansted - declined to comment.

Airports are currently being seen as popular investments because of a surge in air travel worldwide.

Increased offer?

Experts widely predict that a higher offer for BAA will be tabled by Ferrovial or another bidder.

BAA AIRPORTS Heathrow Gatwick Stansted Southampton Glasgow Edinburgh Aberdeen Check BAA shares

Shares in the airports group closed at 836 pence on Friday - valuing it at more than �9bn ($16.9bn) - a higher price than the 810p a share offered by Ferrovial.

BAA also recently rejected a 870-pence-per-share offer from a consortium led by Goldman Sachs.

Since talk of a takeover emerged, BAA has pledge to invest �9.5bn in upgrading its airports over the next 10 years as well as focusing on the growth potential of its assets.

The company has until 29 May to unveil its official defence against Ferrovial's bid.