British police have appealed for internet users worldwide to spread a new video aimed at pricking the conscience of key witnesses who may know what happened to Leicestershire girl Madeleine McCann.

The one-minute film includes fresh images of how Madeleine might look now, including one with dark brown hair and tanned skin in case she has been living in North Africa.

The appeal, launched by the Child Exploitation and Online Protection centre, is targeted at a friend or relative of the person responsible for the Rothley girl's disappearance.

Ceop head Jim Gamble said the clip's message, which has been translated into six other languages, was crafted with the help of psychologists to persuade the witness to "do the right thing".

He said: "The person we are looking to reach is likely to be a partner, family member, friend or colleague of the person or people who were involved in Madeleine's disappearance.

It is also highly probable that they, or someone close to them, is using the internet to search for any updates that may suggest the police are getting closer to discovering the truth." Madeleine was nearly four when she went missing from her family's holiday apartment in Praia da Luz in Portugal on May 3, 2007 while her parents dined with friends nearby.

Ceop hopes people will spread the new film - the first appeal of its kind - across the globe using blogs, e-mail and social networking sites such as Facebook and Twitter.

It features a number of well-known photographs and video clips of Madeleine, as well as three pictures of how she could look now, aged six, if she is still alive.

The US National Centre for Missing and Exploited Children, which developed the age-progression images, released one in May to coincide with the second anniversary of her disappearance. But following concerns that it looked "too American", the two fresh pictures have been created.

Key events since the girl's disappearance

2007

• May 3 - Kate and Gerry McCann, from Rothley, Leicestershire, leave their three children asleep in their holiday apartment in Praia da Luz in southern Portugal while they dine with friends at a nearby tapas restaurant. Nothing is amiss when Mr McCann checks on the youngsters at just after 9 p.m., but when his wife goes back at about 10 p.m. she finds three-year-old Madeleine missing. Jane Tanner, one of the friends eating with the McCanns, later reports seeing a man carrying a child away earlier that night.

• May 5 - Portuguese police reveal they believe Madeleine was abducted but is still alive and in Portugal, and say they have a sketch of a suspect.

• May 14 - Detectives take Anglo-Portuguese property developer Robert Murat in for questioning and make him an "arguido", or official suspect. Officers also search the home he shares with his mother in Praia Da Luz, just 100 metres from where the youngster was snatched.

• May 25 - Portuguese detectives finally release the description of the man reported by Jane Tanner three weeks earlier following pressure from the McCanns, their legal team and the British government.

• May 30 - Mr and Mrs McCann meet the Pope in Rome in the first of a series of trips around Europe and beyond to highlight the search for their daughter.

• August 6 - A Portuguese newspaper reports that British sniffer dogs have found traces of blood on a wall in the McCanns' holiday apartment.

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

• September 7 - During further 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.

• October 25 - The McCanns release a new artist's impression drawn by an FBI-trained expert showing the man described by Jane Tanner.

2008

• February 4 - Portugal's top detective, Alipio Ribeiro, says in a radio interview that police were "hasty" in making Madeleine's parents suspects in her disappearance.

• April 7 - Three Portuguese detectives fly to Britain to re-interview the seven friends on holiday with the McCanns when Madeleine vanished.

• April 10 - Speaking in Brussels, Mr and Mrs McCann call for a Europe-wide missing child alert system.

But this is overshadowed by a leak of the couple's first police interviews, which reveals that Madeleine asked her mother on the morning before she vanished: "Mummy, why didn't you come when we were crying last night?"

• May 3 - A tearful Mrs McCann urges people to "pray like mad" for Madeleine as she and her family mark the first anniversary of the little girl's disappearance.

• July 21 - The Portuguese authorities shelve their investigation and lift the "arguido" status of the McCanns and Mr 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 May 3.

• 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

• January 29 - Nearly £2 million was raised for the official fund to find Madeleine in the first 10 months after she went missing, Companies House accounts show.

• April 4 - Mr McCann goes back to Portugal to help film a reconstruction of the events on the night his daughter vanished for a Channel 4 documentary.

• May 1 - An age-progression image of how Madeleine might look aged six is released as part of an appearance by the McCanns on US television presenter Oprah Winfrey's chat show.

• May 22 - It emerges that private detectives working for the McCanns are investigating a convicted British paedophile called Raymond Hewlett who was staying near Praia da Luz when Madeleine went missing.

• August 6 - The McCanns' investigators launch a worldwide hunt for an Australian lookalike of Victoria Beckham seen at a marina in Barcelona three days after the little girl disappeared.

• September 9 - Lisbon's main civil court bans further sale or publication of Mr Amaral's book following legal action by Mr and Mrs McCann.

• November 3 - The Child Exploitation and Online Protection centre releases an internet video aimed at pricking the conscience of a friend or relative of the person responsible for Madeleine's disappearance.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.