A viral message directed at a friend, relative or partner of the person who abducted Madeleine McCann, telling them that “it is never too late to do the right thing”, went online at midnight.

The video was created to “infiltrate the internet” by spreading from news websites to blogs and social networks until it is the first thing that appears when the missing child’s name is typed into a search engine.

Jim Gamble, the head of the Child Exploitation and Online Protection Centre, said that the message was founded on the belief that, like Jaycee Dugard in California and Natasha Kampusch in Austria, Madeleine could be rescued or reappear despite being missinghaving gone missing for more than two years ago.

“This is about hope, it’s about collective hope. I believe this message will deliver answers for us,” said Mr Gamble, who studied 11 child abduction cases in which the victims had reappeared after long periods in captivity.

Mr Gamble launched “A Minute for Madeleine” with a plea to internet users to view the video and disseminate it.

Harnessing the power of the viral message is a new technique in an investigation but the core idea of the 60-second film is based on the old detective’s adage that “everyone has a best friend” and someone will talk.

Madeleine was 3 years old when she went missing on a family holiday in Portugal in May 2007. The new video contains “aged progressed” images of how she might look today, aged 6. One shows the girl with blonde hair, while the other shows her with dark hair and tanned skin, as she might look if she was being held in a hot country.

The message has gone online in seven languages — English, Arabic, Portuguese, Spanish, French, German and Italian — and will be promoted around the world by police forces, missing persons agencies and Interpol.

It represents the first time that a British law enforcement agency has taken the lead in the international hunt for the missing girl. Her mother, Kate McCann, will conduct a series of television interviews today to promote the message.

Mr Gamble stressed that the video was not a public appeal but a message to one person who knew or suspected that someone close to them had taken the child. “It’s aimed at prompting the conscience of the person who is keeping the secret,” Mr Gamble 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.” He said he believed that the abductor would be regularly checking the internet for developments in the investigation and would be “rattled” by the video, which was prepared with the help of psychologists.

Mr Gamble said: “This is not the normal criminal psychology approach. We’re not looking at the criminal, but at the associate and saying to them, ‘You can redeem yourself’.

“We believe there is someone out there who is associated and who knows. This person doesn’t need to see an age progressed image of Madeleine — this person knows who Madeleine is and who committed the crime.” Mr Gamble stressed that there were no new leads, nor fresh intelligence behind the launch of the message. He added: “In a case like this the investigation is never closed”.

ABDUCTED ... AND FOUND

Natascha Kampusch was abducted aged 10, in 1998 in Vienna. She was found, aged 18, in 2006

Shawn Hornbeck was abducted aged 11 in 2002 in Richwood, Missouri, and held captive for more than four years

Jaycee Lee Dugard was abducted aged 11 in Lake Tahoe, California in 1991 and found this year aged 29

Sabine Dardenne was abducted aged 12 in Belgium in May 2006 and held for 80 days

Sano Fusako was abducted aged 10 in Narita, Japan, in 1990. She was held captive for more than nine years and found in 2000

Jeremiah Treanor was abducted with his brother Marcuse at age 7 in 1980 in London. Held by a child prostitution ring that carried out 38 kidnappings. Found alive in 1983. His brother died

Times Recommends

• Please help: maimed children of war want their lives back
• Unlocking the cruellest prison
• Prince Charles named in £81m court battle