BAA is due to be awarded rights to run Italy’s second biggest airport in a deal worth around £500m.
The contract for Rome’s Fiumicino, and the regional Ciampino airport, will go to BAA if, as expected, it beats three other bidders.
The Italian government is selling a controlling stake, believed to be 51.2%, in Aeroporti di Roma, which runs the two hubs.
Rome will be BAA’s biggest operation in mainland Europe. The firm already runs Italy’s Naples Airport.
Fiumicino handles 25m passengers a year and is Alitalia’s second hub, after Milan. The size of the airport gives BAA opportunities to use its retail experience to boost revenues.
Other bidders include a consortium put together by Dutch bank ABN AMRO, Schiphol airport and Frankfurt airport.
The expansion into worldwide operations comes as BAA faces calls for its hold on south-east airports to be broken.