6 May 2012 Last updated at 06:21 ET

Missing runner John Lawton: Search continues

John's wife Lynda raised the alarm when he failed to pass the finish line four weeks ago

The son of a Cheshire long distance runner who disappeared in Greece four weeks ago has said "it's getting harder" to believe he will be found.

John Lawton, 62, from Alsager, went missing in an off-road race on 8 April.

His son Steve said: "We'd always thought, hoped and prayed it was only a matter of hours before we found him so it's getting even harder now."

More than £12,000 has been donated to an online collection to ensure the search can continue.

Members of Mr Lawton's club, Sandbach Striders Running Club, have flown out to Greece to join in the search.

His son said the official search had been called off and they were relying on a small team of volunteers for help.

Last month, six people from the running club took part in the London Marathon with pictures of Mr Lawton on their backs to raise funds for the search.

His brother David has also been in Greece to help.

Mr Lawton's wife Lynda raised the alarm when he failed to pass the finish line of the Taygetos Challenge 2012, near Kalamata, in western Greece.