British Prime Minister David Cameron has welcomed the decision by British detectives to launch their own investigation into the disappearance of Madeleine McCann.
Mr Cameron said the case of the then three-year-old who went missing from a holiday apartment in Portugal's Algarve in May 2007 was one that continued to shock Britain.
Scotland Yard said on Thursday it was launching its own investigation into her disappearance.
It said it had "genuinely new" lines of inquiry and believed there is a chance she is alive.
Speaking at Evelina Children's Hospital in London yesterday during celebrations of the 65th birthday of the National Health Service, Mr Cameron said: "It is welcome because they say that there is new evidence, new leads to follow, new things to be done.
"It was a case that did shock and still shocks the nation and if an answer can be found we should try and find it."
The Metropolitan Police says that detectives had identified 38 people of interest, including 12 UK nationals following a two-year review of evidence in the case.
None of the 38 people identified are known to the McCanns.
Clarence Mitchell, the family's spokesman, said: "Kate and Gerry warmly welcome this shift in the Metropolitan Police emphasis.
"They see it as a huge step forward in establishing what happened and hope that it will lead to bringing to justice whoever was responsible for Madeleine's abduction."
Madeleine went missing from a holiday apartment in Praia da Luz in Portugal's Algarve on 3 May 2007, as her parents Kate and Gerry dined at a nearby tapas restaurant with friends.
Neither her parents nor the McCanns' friends who were having dinner with them that night are among the 38 people identified, police said.
The Portuguese investigation is officially closed, but authorities there are backing the Scotland Yard inquiry and officers from both countries will work together in pursuing new leads.
A team of 37 Met police officers and staff are working on the case, and they are sending a formal letter of request to Portuguese authorities for help.
Detective Chief Inspector Andy Redwood, who is leading the investigation, said his team has carried out new witness interviews and was in a "unique position" in analysing information from police in Portugal and the UK, as well as seven private detective firms.
He said: "That has given us the ability to see this case with fresh eyes, and through that bring out new, genuinely new, lines of inquiry. And I'm hopeful when we pursue those lines of inquiry that we will be able to bring some sort of resolution.
"Whether we will be able to solve it is a different issue, but I hope that we will be able to have the ability to move the investigation on.
"I believe critically that this is an important moment for Madeleine. It is the culmination of that unique piece of work and it is a great opportunity which we intend to exploit to the full."
The 12 British persons of interest were in Portugal at the time Madeleine vanished, and are currently thought to be in Portugal or the UK.
The remainder are believed to be in these countries or three other unnamed European nations.
So far the team has gathered 30,500 documents and generated 3,800 actions that they need to tackle.
They are around two-thirds of the way through their review, and so far have been to Portugal 16 times.
They have interviewed witnesses, found new evidence and are working on new theories about what happened to Madeleine.