Kate McCann was joined by Bob Geldof and Stephen Fry in backing Child Rescue Alerts
Madeleine McCann's mother has called on members of the public to sign up to a scheme designed to save the lives of missing children.
Kate McCann, 47, is among several high-profile figures taking part in a two-week campaign to promote Child Rescue Alerts.
The nationwide service, also backed by Bob Geldof and actor Stephen Fry, sends out free alerts to registered members of the public when a child goes missing or their life is thought to be at risk.
Mrs McCann said that if a similar system had been in place when three-year-old Madeleine went missing from the family's holiday apartment in Praia da Luz in Portugal in 2007, it is possible she may have been found.
"If enough people had been mobilized and galvanized early then who knows what the outcome would have been," she told The Sun.
She said that her research over the years had led her to believe that her daughter's kidnapper did not take her far from the Algarve.
"That's where she last was and I don't think she's been taken a million miles from there. I've always said Praia da Luz is the place where I feel closest to her. The urge to look for Madeleine absolutely hasn't changed at all. You hear all the time about people who have been missing for years being found. There have been so many cases like that. We will never give up. You couldn't settle if you thought about giving up. I want an end, an answer. Whatever that it is."
Fry is the face of the Child Rescue Alerts, appearing in adverts and posters a comic book version of himself.
As part of the two-week campaign, adverts will appear in shopping centres, the London Underground and railway stations across the UK.
The system, which was first set up in 2008, is run by the National Crime Agency, the charity Missing People and the education technology company Groupcall, which was co-founded by Geldof.
Promoting the alerts earlier this year, Geldof said they were a "no-brainer".
"If your child went missing and their life was in immediate danger you would want to get the message out in minutes," he said. "If you care about children's safety please sign up today at childrescuealert.org.uk."
The programme will involve members of the public can registering for geographically-targeted texts, emails or app notifications.