Scotland Yard want to interview three burglars over the disappearance of Madeleine McCann, it has been revealed.
The suspects had carried out raids in the Praia da Luz area, at the time the three-year-old disappeared.
The Metropolitan Police requested the Portuguese police for more help with their inquiry, suggesting new leads or suspects had been identified.
According to a report in the Daily Mirror, British officers were preparing to fly out to Portugal to make the arrest.
Records revealed the men in question made numerous phone calls to each other after Madeleine vanished. Days before she disappeared in May 2007, the men burgled an apartment nearby, disturbing a child. The parents interrupted the intruders, who fled.
The Crown Prosecution Service sent the second "International Letter of Request" to the Portuguese authorities on behalf of the Metropolitan Police last week, to seek the arrest of the men.
A Metropolitan Police spokesman confirmed the sending of the letter on Friday: "We can confirm that a second International Letter of Request has been sent to the Portuguese authorities by the Crown Prosecution Services this week in connection with Operation Grange."
A spokesperson for Kate and Gerry McCann, Madeleine's parents, said:
"The letter is a significant development. It is necessary for British police to request the Portuguese authorities allow them to operate on their turf.
"It means they have the intention of arresting and interviewing X, Y or Z. We don't know who they have their sights on but it's likely it is the burglars.
"Whether the Portuguese will co-operate remains to be seen. It is a very sensitive issue with differences they have had.
"Police want to be given a chance to arrest key suspects. It doesn't prove they have Madeleine but it will rule them in or out of the investigation and that is important.
"Kate and Gerry don't want to build up their hopes too high but they realise it could be a significant new lead."
The International Letter of Request was sent by Scotland Yard because they lack the jurisdiction to operate overseas. In order to follow their lead, they must ask their equivalent abroad to investigate and arrest on their behalf.
Member states are expected to comply under European Union rule of Mutual Legal Assistance Treaties.
Members of the European Union are expected to comply with requests like these, made under Mutual Legal Assistance Treaties.