The parents of a man who vanished while trekking in Nepal have set off on a 190-mile walk to raise awareness and funds for a charity dedicated to finding missing people.

David and Gillian Koch, from Wantage, are tackling the Coast to Coast route across England to highlight the case of their son Gareth, 24, who went missing in 2004, and support the work of the National Missing Persons Helpline (NMPH).

Gareth disappeared on a trekking holiday in Nepal. Last seen in Chhukung on March 8, 2004, he was due to fly home soon afterwards but did not catch his flight.

The Koch family and NMPH, the UK's only organisation dedicated to finding missing people and supporting those left behind, have campaigned for two years to try and find out what happened to Gareth, but his fate remains a mystery.

David Koch, who turns 50 tomorrow, said: "We wanted to do something special to celebrate my birthday while raising vital funds for NMPH's Summer Search campaign.

"They are a wonderful organisation and they have given us so much support over the last two years.

"We also hope the publicity from this walk will lead to new information as to what happened to Gareth."

Mr and Mrs Koch yesterday left St Bees, Cumbria, and hope to reach Robin Hood's Bay in North Yorkshire on July 2.

NMPH's Summer Search campaign was launched on May 15, Missing Persons Awareness Day, and aims to highlight the estimated 70,000 people who go missing each summer.

As part of the campaign, NMPH is asking the public to make a donation of £1.50 to the charity by texting missing' to 84010. A one-off return text will be sent displaying details of a missing person that will be changed monthly during the four month campaign.

Other initiatives launched include appeals for eight of the nation's missing children on T-shirts, which are being sold through the website www.missingpersons.org for £9.99.

NMPH spokesman Ross Miller said: "We hope that everyone, whether they have experienced a family member go missing like the Kochs or perhaps just seen one of our missing' appeals, will support this important campaign."

If you have any news regarding Gareth's whereabouts, contact the confidential National Missing Persons Helpline on freephone 0500 700 700. Alternatively, email sightings@- missingpersons.org