Analysis of mobile phone data suggests a burglary gang was operating very near to where she vanished in Portugal in May 2007.
The three men made an unusually high number of calls to each other in the hours after Madeleine was reported missing from her holiday flat in the Algarve.
Police believe the thieves, including at least one Portuguese man, had already carried out one raid in the resort of Praia da Luz, disturbing a child.
That child’s parents, who had been drinking outside the property, rushed inside to find the intruders had fled.
During their bungled investigation Portuguese police attached no significance to the break-in, which came a few days before Madeleine disappeared.
British detectives said this oversight was a ‘disgrace’.
Following the Yard phone breakthrough, informal discussions have taken place about arresting the three burglars and searching their homes and other sites.
It is believed background checks have taken place into their criminal history, their circle of friends and relatives and the vehicles they have used.
British detectives believe the burglars may have panicked after they woke Madeleine up by mistake and decided to take her away with them.
Kate and Gerry McCann pose with an artist's impression of how their daughter might look at the age of nine last year
An informed source said: ‘After all the
far-fetched theories about what may have happened to Madeleine, there
may be a far more simple explanation: that a burglary went horribly
wrong. 'It is the main line of inquiry for British police.’