Madonna is planning to fly to America to adopt the African boy she flew into London.

Sources in Los Angeles say she has hired an American adoption agency because she fears British authorities could block her bid to become mother to 13-month-old David Banda.

It can also be revealed the star is taking the advice of friends Brad Pitt and Angelina Jolie to pursue the adoption in California.

The moves come after it emerged Madonna and husband Guy Ritchie could face a criminal investigation by British authorities after she brought David from Malawi yesterday.

It is not clear whether she has set in motion the vetting procedure all prospective parents must go through before being allowed to adopt there.

Social services sources have questioned the legality of the adoption and suggested an inquiry is likely to take place.

They expressed surprise they had not been contacted by the star before the baby was brought into the country.

Madonna, 48, could face serious obstacles in the UK because of her age, despite her wealth and fame. But she is thought to be following US procedures where the rules are much more flexible about allowing older parents to adopt.

In the summer, the singer reportedly began the adoption process at the Vista Del Mar agency in Los Angeles. They were said to have begun evaluation as prospective adoptive parents. The report said they were fingerprinted and interviewed by the agency's adoption experts.

In a statement issued by the singer, Madonna suggested she has already taken steps to begin the legal adoption process. She said: "We have gone about the adoption procedure according to the law like anyone else who adopts a child.

"Reports to the contrary are totally inaccurate. The procedure includes an 18-month evaluation period after which time we hope to make this adoption permanent. This was not a decision or commitment that my family or I take lightly."

Madonna and Ritchie have been in close touch with Jolie and Pitt from the early stages of the Malawi adoption planning.

Pitt has been friends with Ritchie since they worked together on the film Snatch in 2000. He and Jolie went through their own turbulent adoption of daughter Zahara, in Ethiopia, that was only resolved after overcoming mounds of red tape.

The couples discussed the adoption after they met at a London restaurant in January, when Pitt and a still- pregnant Angelina were staying at Claridge's, according to a friend in Los Angeles.

They also saw each other on the LA leg of Madonna's world tour. The friend added: "Brad and Angelina know all about the adoption and have been helping Madonna and Guy in every way they can. They know how important it is to them and how difficult the process can be."

It is understood that Pitt and Jolie gave them details of their adoption lawyer. The couple have a five-year-old son, Rocco, together, and the singer has a nine-year-old daughter, Lourdes, by former lover Carlos Leon. Pitt and Jolie are currently filming in India.