Spain's Grupo Ferrovial said on Tuesday it was willing to drop a condition in its bid for airports firm BAA by going unconditional, even if the offer was not supported by three quarters of BAA's shareholders.

In its April 20 offer document, the Spanish construction and services firm said it had agreed with its banks not to declare the offer unconditional until it had received acceptances for more than 75 percent of BAA shares.

But in a statement to the London and Madrid stock exchanges on Tuesday, Ferrovial said: "If the Banks so consent, (bid vehicle) ADI would be able to declare the share offer unconditional as to acceptances at a level lower than the threshold set out above.

"In any event, the 50 percent acceptance condition... must be satisfied," Ferrovial said.

Ferrovial said on May 19 it had acceptances from shareholders owning just 0.35 percent of BAA.

BAA, the owner of London's Heathrow, Gatwick and Stansted airports, has rejected Ferrovial's GBP