The Portuguese Attorney General has confirmed to ITV News that an International Letter of Request has now been received from detectives investigating the disappearance of Madeleine McCann.
Joana Marques Vidal said the letter from officers at the Metropolitan Police has now been passed to a Portuguese court for consideration.
Two weeks ago officers involved in Operation Grange, the code-name for the British investigation, confirmed they had asked colleagues in the Algarve for assistance.
It is thought they want to speak to a number of men about a large number phone calls they made in the area on the night the child vanished.
It was reported the three were known burglars. Under Portuguese law British officers have to go through local police in order to gain information for their investigation if those involved are based in Portugal.