British police have they were looking at new cell phone data to advance their investigation into the disappearance of Madeleine McCann, who vanished from a resort in Portugal six years ago.

Madeline, who was three years old at the time, went missing from her room at the Praia da Luz holiday resort in the Algarve in May 2007, leading to a global search.

A new inquiry in Britain, which began two months ago, is focused on thousands of phone records from the resort at the time.

London police said they had made 31 requests in various countries for information concerning telephones used then.

There are 41 potential suspects, described as “persons of interest”, and 15 are British nationals.

British authorities launched a review of the case in 2011 after Madeline's parents wrote to British Prime Minister David Cameron saying not enough was being done to find their daughter.

Portuguese police hired six officers in Faro to carry out inquiries on behalf of British police, though this does not mean that they have or will reopen the investigation.

The two forces will meet to discuss the case in a few weeks time.