A new team of detectives has been set up by the Portuguese police to review the investigation into the disappearance of Madeleine McCann.

An outside squad of officers has been brought in to re-examine the case of Madeleine McCann almost four years after the police probe was formally archived.

The new team, from the northern city of Porto, has been instructed to go over the thousands of pages of case files and search for new clues.

The development will provide fresh hope for parents Gerry and Kate McCann, who have never given up on finding their daughter alive.

They have repeatedly called on the Portuguese authorities to resume the search for their daughter.

The case review is being carried out by Policia Judiciaria’s Regional Section of Criminal Investigation and Prevention in Porto, led by Helena Monteiro.

Madeleine McCann was nearly four when she went missing from her family’s holiday flat in Praia da Luz in the Algarve on May 3, 2007 as her parents Kate and Gerry dined with friends nearby.

Portuguese detectives, helped by officers from Leicestershire Police, carried out a massive investigation into her disappearance. The official inquiry was formally shelved in July 2008.

The family’s Portuguese lawyer Rogerio Alves described the Portuguese police case review as a “very positive sign”.

Rogerio Alves said: “More than anything Kate and Gerry want to discover what happened to their daughter, whilst of course harboring the hope of finding her alive.

“For that to happen, the police need to carry on looking for her and carrying on following the leads at their disposal.”

A new team of detectives has been set up by the Portuguese police to review the investigation into the disappearance of Madeleine McCann

Rogerio Alves also said he believed the review could lead to an eventual reopening of the case.

The lawyer told a Portuguese TV station: “It’s not absolutely certain but what’s happening at the moment is that some of the information passed to the authorities could lead to a reopening of the case.

“Obviously within this enormous universe of people who say they’ve seen one thing or another or have information on one thing or another, the police make a selection.

“I can’t go into any sort of detail and I hope people will understand me, but at this moment in time there is something that aroused enough interest from the Portuguese and British police to warrant this review in search of new clues.

“This is all I can say but obviously the most plausible explanation for what’s happening is this one, that information passed to or acquired by the Judicial Police in Porto has put them on the trail of something specific.

“I don’t have detailed information and as you’d expect they’re always going to be cautious in releasing information.”

Detectives from Porto are understood to have travelled to the Algarve as part of the review.

The Policia Judiciaria’s deputy national director Pedro do Carmo told newspaper Jornal de Noticias they wanted detectives who had no previous involvement with the case to take a fresh look at the investigation.

Pedro do Carmo said: “Despite having been formally archived, we continue to have an unexplained disappearance. The archiving does not mean that the Policia Judiciaria (PJ) have less interest in establishing what happened or looking for answers.

“The British authorities have set up a team to review the investigation. They have been to Portugal and agreed to collaborate with the PJ. We are doing the same.

“The Porto team is experienced in these cases.”

Pedro do Carmo stressed that the case had not been reopened and still officially remains archived.

A spokeswoman for the PJ said today: “The leadership of the PJ wants to have another look at the case and to work with the British authorities and they have chosen an experienced team from Porto to do this.

“In Portugal only the attorney general’s office can order the reopening of a case and it would only do that if there was strong new evidence. At the moment that has not happened.”

The Scotland Yard review, called Operation Grange, involves 30 murder squad detectives, some of whom have made at least four trips to Portugal and Spain.

In December 2011 they travelled to Barcelona to meet with private investigators from the agency Metodo 3, who were hired by the McCanns to find their daughter.

Madeleine McCann’s parents, both doctors from Rothley, Leicestershire, have previously welcomed Scotland Yard’s involvement in the case.

McCann family spokesman Clarence Mitchell said: “Kate and Gerry obviously welcome the work being done by the PJ in Oporto alongside that of the Met investigative team.

“They clearly hope that it will lead to the case being reopened in due course.

“There is good co-operation between the Met and the PJ, and Kate and Gerry remain grateful for the time and resources that have been put into the search for Madeleine.

“They will not be discussing any details whilst both the Met investigative review and the PJ work is continuing, but clearly it is a positive development.”