Madeleine McCann: Met Police still pursuing 'critical' leads 10 years after disappearance but have 'no evidence' if she is alive or dead

Detectives hunting for Madeleine McCann are still pursuing "critical" leads but have no evidence as to whether she is alive or dead, Scotland Yard has revealed.

As the tenth anniversary of her disappearance approaches, Assistant Commissioner Mark Rowley said there are "significant investigative avenues" of "great interest" to police.

But he would not reveal police theories or speak about potential current suspects, saying that disclosing further detail would not help the investigation.

Madeleine, who was aged three at the time, vanished from the family's holiday apartment in Praia da Luz in Portugal on May 3 2007.

Her parents, Kate and Gerry McCann, of Rothley, Leicestershire, have vowed to "never give up" hope of finding their daughter.

Asked if police were any closer to solving the case than they were six years ago when the UK investigation was launched, Mr Rowley said: "I know we have a significant line of inquiry which is worth pursuing but until we've gone through it I won't know whether we are going to get there or not.

"Ourselves and the Portuguese are doing a critical piece of work and we don't want to spoil it by putting titbits of information out publicly."

He said he did not have "definitive evidence" as to whether Madeleine is alive or dead, adding: “That's why we describe it as a missing person inquiry. We understand why, after this many years, people will be pessimistic, but it's important we keep an open mind."

He described the possibility of a "burglary gone wrong" as a "sensible hypothesis" which has not been "entirely ruled out” and also said theories of a sex predator being responsible had also been considered.

"That's been one key line of inquiry,” he said. “The reality is in the modern world in any urban area if you cast your net widely … You will find sex offenders who live nearby.”

"Offences which may be linked have to be looked at and either ruled in or ruled out,” he added.

But Mr Rowley said that, however Madeleine left the apartment, she was abducted, saying: “She wasn't old enough to make a decision to set off and start her own life.

“This is a young girl who is missing and so there has to, at the heart of this, at least have been abduction.”

He said there was still much “unknown" in the case but that Operation Grange, which was set up in 2011, had achieved "an awful lot".

Since it was established, police have looked into more than 600 individuals and 40,000 documents.

In 2013 the team identified four people as suspects in the case. Interviews and searches were carried out but no evidence was found to implicate the four in the disappearance. They have now been ruled out of the inquiry.

In 2014 British detectives flew out to Portugal, sparking suspicion that they were about to carry out an arrest.

Met officers were accompanied by archaeologists and sniffer dogs to search 60,000 square metres of land but nothing is believed to have been found.

Last month the Home Office confirmed £85,000 was being given to police to cover operational costs from April to September. More than £11 million has been spent on the inquiry so far.

The assistant commissioner acknowledged that “big cases” require “a lot of resources” but said he has “tried to be careful about public money”.

"I think people get seduced perhaps by what they see in TV dramas where the most complex cases are solved in 30 minutes or 60 minutes,” he said.

“What we started with here was something extraordinary. We've achieved a complete understanding of it all. We've sifted out many of the potential suspects, many of the people of interest and where we are today is with a much smaller team focused on a small number of remaining critical lines of inquiry that we think are significant.

Timeline of Madeleine's dissappearance

2007

May 3 - The McCann's leave their children asleep whilst they dine at a nearby restaurant. When Kate goes to check on the children at 10pm she finds three-year-old Madeleine missing. Jane Tanner, one of the friends dining with the McCanns, reports seeing a man carrying a child earlier that night.

May 4 - Sniffer dogs are brought in, the Spanish and border police and airports are notified, and volunteer teams continue combing the village, resort and beach for clues.

May 14 - Detectives take Anglo-Portuguese property developer Robert Murat in for questioning and make him an "arguido", or formal suspect.

August 11 - 100 days after Madeleine disappeared, investigating officers publicly acknowledge for the first time that she could be dead.

September 7 - During questioning of Mr and Mrs McCann, detectives make them both "arguidos" in their daughter's disappearance.

September 9 - The McCanns fly back to England with their two-year-old twins Sean and Amelie.

October 2 - Goncalo Amaral, the detective in charge of the inquiry, is removed from the case after criticising the British police in a Portuguese newspaper interview.

November 6 - Chairman of the Portuguese Union of Police Detectives, Carlos Anjos, says the McCann family have helped create an unhelpful "monster of information" by seeking a high-profile press campaign.

2008

July 21 - The Portuguese authorities shelve their investigation and lift the "arguido" status of the McCanns and Robert Murat.

July 24 - Mr Amaral publishes a book about the case, entitled The Truth Of The Lie, in which he alleges that the young girl died in her family's holiday flat on the day she went missing. He later takes part in a documentary for Portuguese television in which he claimed that Madeleine was dead, that there had been no abduction and the McCanns had hidden her body.

August 4 - Thousands of pages of evidence from the Portuguese police files in the exhaustive investigation into Madeleine's disappearance are made public. They reveal details of the lines of inquiry pursued by detectives, witness statements and scores of previously unknown sightings of the little girl.

2009

May 1 - Kate and Gerry McCann appeal for new information and release a computer-generated image depicting how Madeleine might look two years after she first disappeared.

September 9 - A Portuguese judge bans further sale or publication of Mr Amaral's book following legal action by Mr and Mrs McCann. This injunction is later upheld before being overturned on appeal.

2011

May 12 - Mrs McCann publishes a book about her daughter's disappearance, on Madeleine's eighth birthday. Scotland Yard launches a review of the case after a request from Home Secretary Theresa May supported by Prime Minister David Cameron.

2012

April 25 - Scotland Yard detectives say they believe Madeleine could still be alive, release an age-progression picture of how she might look as a nine-year-old, and call on the Portuguese authorities to reopen the case, but Portuguese police say they have found no new material.

2013

July 4 - Scotland Yard confirms that it has launched its own investigation into Madeleine's disappearance two years into a review of the case. It has "genuinely new" lines of inquiry and has identified 38 people of interest, including 12 Britons.

October 24 - Portuguese police confirm that a review of their original investigation has uncovered new lines of inquiry, and reopen the case.

November 27 - Metropolitan Police Commissioner Sir Bernard Hogan-Howe said British and Portuguese police should join together as one team in their investigations.

2014

January 29 - British detectives fly to Portugal amid claims they are planning to make arrests.

June 3 - Sniffer dogs and specialist teams are used to search an area of scrubland close to where Madeleine went missing.

2015

September 16 - The Government discloses that the investigation into the disappearance of Madeleine has cost more than £10 million. Scotland Yard's investigation into the disappearance has been cut from 29 officers to four.

2016

April 3 - Home Secretary Theresa May grants UK police Operation Grange £95,000 to continue. Police confirm the investigation will be extended for a further six months.

2017

January 31 - Portugal's Supreme Court rules against the McCanns' 500,000 euro (£418,000) libel claim against Goncalo Amaral. Court officials say the claims made in his book are protected by freedom of expression laws.

March 11 - Home Office grants Operation Grange £85,000 to continue between April and September.

“We will stick with it as long as the funding's available and as long as there are sensible lines of inquiry to pursue."

He added: “What I've always said on this case, and I've said it to Kate and Gerry as well, we will do everything reasonably possible to try and find an answer.

"I just can't quite guarantee it. It always hurts that you can't guarantee success but we will do everything we reasonably can do to try and get there."