chief executive Paul Tuohy said: "Everyone hopes that Madeleine's disappearance will have a swift and happy ending.
There is growing concern for Elizabeth's welfare and we urge her to contact us to let us know that she is OK," added the NMPH
therefore guarantees confidentiality to seekers and found alike.
receives thousands of missing persons reports every year, but on a positive note the charity helps to resolve 70 per cent of cases it works on.
But as the NMPH
points out, many people disappear just because they want to.
recognises the right to stay out of touch and can forward an `alive and well' message to put relatives' minds at rest without revealing the senders' whereabouts.
The police tend not to actively look for people except in cases of vulnerability or crime and regularly refer cases to NMPH
charity say people go missing for a variety of reasons, including family conflict, debt, illness or accident, abuse, and general anxiety or stress
I've never been in the situation of needing the services of NMPH
but know from speaking with those waiting for news of their loved ones that the care and support received from the charity has enabled them to cope with their lives.
As volunteers and workers from the NMPH
released 500 balloons above The Mound in Edinburgh to herald the start of the walk last Thursday, another couple joined the Burns for the first leg of the trek - Derek's old school pal Ian Dickson, 34, and his wife Elizabeth.
was closely involved in the project, choosing the photos which could be used, and each image is accompanied by details of the person's disappearance.
If you want to support the NMPH
then phone 0208 3924592 or log on to www.