London - A suspect was identified on Wednesday night over the abduction of Madeleine McCann.
In the biggest breakthrough since her disappearance 13 years ago, detectives are investigating a German sex offender.
They revealed the 43-year-old, who is in prison in his homeland, has convictions for abusing children.
And he is suspected of burgling hotel complexes and tourist flats as well as dealing in drugs. The German officers suggested he may have broken into the McCann family’s holiday apartment in Portugal and kidnapped her.
The suspect, who has not been named, was renting a ramshackle farm building 3km from Praia da Luz where the McCanns were staying.
British detectives believe that at the time of her disappearance in May 2007 he was living out of a battered VW camper van in the resort.
They think the suspect may have bundled three-year-old Maddie into the vehicle after abducting her from the Algarve apartment.
They have launched a major appeal for information about the van but also over a Jaguar car seen in the area and linked to the suspect.
Scotland Yard has found the suspect took a call on his cellphone placing him in Praia da Luz between 7.30pm and 8pm on the night they believed Madeleine was dead, they said: "There is reason to assume that there are other persons, apart from the suspect, who have concrete knowledge of the course of the crime and maybe also of the place where the body was left. We explicitly ask these persons to contact us and provide information."
Christian Hoppe, of Germany’s Federal Criminal Police Office, told the ZDF television channel that the suspect was serving a prison sentence for a sex crime and had two previous convictions for "sexual contact with girls".
Hoppe said German police had not ruled out a sexual motive.
Madeleine’s parents Kate and Gerry said they would "never give up hope" of finding their daughter alive as their 13-year long quest to "uncover the truth" took the extraordinary twist.
"All we have ever wanted is to find her, uncover the truth and bring those responsible to justice," they said. "We will never give up hope of finding Madeleine alive, but whatever the outcome may be, we need to know as we need to find peace."
Madeleine McCann, who would have turned 17 on May 12, disappeared while her parents, from Rothley in Leicestershire, were having a meal with friends at a tapas bar close to their apartment at an Algarve resort on May 3, 2007.
Her disappearance quickly became one of the most high profile missing persons cases in modern history, with the inquiry dominating headlines for months. Despite a huge number of twists and turns, it has never been solved.
Since the start of Operation Grange, the Scotland Yard probe into the case, £12 million has been spent. Now it appears detectives have narrowed the search from 600 persons of interest to just one.
The suspect, who was 30 at the time, is described as white with short blond hair, possibly fair, and about 1.8m tall with a slim build. He was said to have been living a "transient lifestyle" in a white and orange VW campervan in the Algarve resort from 1995 until 2007.Police revealed on Wednessday he had been at the centre of a major international investigation dating back three years in Germany, Portugal and Britain, with officers trying to unravel his movements and his links to Madeleine.
At a briefing on Wednesday, Scotland Yard revealed officers had received a "critical" piece of information about him following an appeal on the 10th anniversary of Madeleine’s disappearance.
They had previously released an e-fit of a blond man seen near the McCann apartment at around 4pm on the day she was snatched.
At the time he was described as white, 30-35, thin, with short, light-coloured hair and spots on his face possibly caused by shaving.
Last night detectives said the e-fit image had never been ruled out of the investigation, suggesting that it might resemble the man they think could be responsible for Madeleine’s abduction.
In Wednesday’s briefing, British police refused to disclose the new suspect’s criminal history, but said he was in a prison for an unrelated matter and was under investigation in Germany for other offences.
In a TV appeal on Wednesday night, German police went further and revealed much more detail about the suspect, saying he had been sentenced to numerous prison terms for child abuse.
They also said there was evidence he had earned money by burgling holiday apartments and flats.
They said police inquiries were homing in on two properties near where Madeleine was staying.
They also said the suspect was driving two "flashy" vehicles, possibly one of the cars used in the crime: a dark red Jaguar XJR 6 and a VW T3 Westfalia.
Police believe it is highly significant that, just a day after Madeleine’s disappearance, the suspect put the ownership of the Jaguar in a different person’s name. The vehicle has since been traced and searched by police in Portugal.
Officers are also appealing for information about the campervan they fear may have played a role in the abduction.
Officers have also taken the highly unusual step of releasing the suspect’s phone number in a bid to trace anyone who may recognise it.
Stuart Cundy, Deputy Assistant Commissioner of Met Police, said: "Until 2017 this man was not a suspect in our investigation.
"Our main line of enquiry is this suspect, he is the main focus of our investigation. This is a significant development, which is why we have taken the step today of making a public appeal. We are committed to finding out if this man was involved in this disappearance.
"We are considering a number of scenarios but are keeping an open mind about any possible motives. We do not have definitive evidence to say Madeleine is alive or dead.
"We are treating it as a missing person not as a murder investigation."
German police are treating Madeleine’s disappearance as a murder investigation however.
Neighbours described the 43-year-old German convicted criminal as an "angry" loner who vanished suddenly, leaving a collection of wigs and fancy dress.