Scotland Yard detectives released a picture of what Madeleine McCann may look like today as they said they had uncovered new information to suggest she could be alive and living with her abductor.
The senior officer leading an investigative review into the disappearance of Madeleine five years ago is calling on Portuguese police to reopen their inquiry into the case.
Releasing an age-enhanced image of Madeleine ? as she nears her ninth birthday on 12 May ? Detective Chief Inspector Andy Redwood, of Scotland Yard's homicide and serious crime command, said: "We genuinely believe there's a possibility that she is alive. I want to make a direct appeal. If you know where Madeleine McCann is or if you have any direct information or evidence about what happened to her, then please make contact."
Redwood and his 37-strong team have identified 195 missed investigative opportunities in the 40,000 pieces of evidence they have examined from the Portuguese inquiry, the family's home force in Leicestershire, and the information gleaned by a team of private detectives hired by the McCann family since Madeleine went missing, aged three, from the resort of Praia de Luz on 3 May 2007.
"We are in a unique position seeking to draw together the three key strands of information about her disappearance," said Redwood.
He unequivocally dismissed the conspiracy theory ? promoted by the original Portuguese lead detective Goncalo Amaral ? that Madeleine's parents had anything to do with her disappearance.
He said detectives believe Madeleine was abducted in "a criminal act by a stranger".
Madeleine's parents, Kate and Gerry McCann, worked closely with the Met to produce the new image of their daughter.
"Kate says she can see Madeleine's brother and sister Sean and Amelie in it as well as something of herself," said the family's spokesman, Clarence Mitchell. She and Gerry feel very positive and they hope it leads to the breakthrough they have been waiting for."
Redwood's team is sifting page by page through 100,000 documents within the 40,000 pieces of evidence, and are a quarter of the way through the exercise. They are working closely with a team of Portuguese detectives and liaising with law enforcement agencies across Europe and the world when necessary.
They are developing what they believe is "genuinely new information" in the hunt for the child. It is understood, though, that this is not based on any new possible sightings. The team is also pursuing the line of inquiry that after five years Madeleine might be dead.
It is understood that key areas being investigated by Scotland Yard ? which the Portuguese police failed to pursue ? include analysis of a huge amount of mobile phone cell site evidence that was gathered but never analysed. That evidence could help to trace any suspects who were around the resort.
They are also attempting for the first time to contact all the holidaymakers who were staying around the area of the Mark Warner Ocean club complex between 28 April and 3 May 2007, when Madeleine disappeared from her room while her parents were eating dinner with friends at a nearby tapas bar.
Officers are also focusing on any men in the area with criminal convictions that might indicate they are a danger to children, and investigating the backgrounds of resort staff, including examining whether any had suffered the loss of a child.
Commander Simon Foy, Scotland Yard's head of homicide command, said they would not stop until they discovered what had happened to Madeleine. The review inquiry ? which has cost £2m to date ? began after the McCanns appealed last year to David Cameron for Scotland Yard to investigate the case.
There are examples of children who have been abducted only to be found alive years later: Jaycee Lee Dugard was found alive 18 years after being snatched at the age of 11 from a bus stop in California; the Austrian schoolgirl Natascha Kampusch was found in 2006, eight years after being abducted aged 10; and Shawn Hornbeck, who disappeared aged 12 in 2002, was found four years later.
The decision on whether to reopen the inquiry in Portugal is in the hands of the country's attorney general. He has said he will only reopen the investigation if "new, serious and relevant evidence emerges". He was not available for comment.
Redwood said the police review team in Portugal were keen for this to happen. "[They] want to reopen the case ? They are a new group of investigators and they are completely engaged and totally committed."
Jim Gamble, former head of the UK's Child Exploitation and Online Protection unit, said the hunt for Madeleine had now been reignited. "The person who's done it knows they have done it," said Gamble. "They will be paranoid, and it is likely that someone close to them will see that paranoia, or that as the pressure builds someone close to them who knows they have done it, and who is no longer a friend, might come forward.
"One thing is sure: the person who did this will be watching and listening."
Potential witnesses are urged to call 0800 096 1011 within the UK or +44 207 1580 126 from outside. Crimestoppers can be contacted anonymously on 0800 555 111.