Images of how Madeleine might look now, including one with dark brown hair and tanned skin

Images of how Madeleine might look now, including one with dark brown hair and tanned skin

British police have appealed for internet users worldwide to spread a new video aimed at pricking the conscience of the key witness who knows what happened to Madeleine McCann who went missing in Portugal in May 2007.

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 (Ceop) centre, is targeted at a friend or relative of the person responsible for the little girl's disappearance.

Ceop hopes people will spread the new film - the first appeal of its kind - across the globe using blogs, email 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.

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

The video has a voice-over in which Mr Gamble appeals directly to anyone with information about what happened to the child.

It is being supported by police agencies around the world, including Interpol, Europol and forces in Australia, the US, Canada and the United Arab Emirates.

Ceop did not work directly with the Portuguese police, who led the investigation into the little girl's disappearance before shelving the case in July last year.

But any relevant information received will be passed on to Leicestershire Police, who will share it with detectives in Portugal.