Mick Tyler, 54, a former SAS soldier with 29 years in the forces, has eight places left on his 'rough country' Christmas survival course.
Recruits will start Christmas Day plunging naked into icy waters before navigating rough terrain, skinning rabbits and catching fish with home-made tools.
'Half-way through the afternoon they will find themselves in a field next to a half-opened parachute,' said Mr Tyler. 'I will be there to serve them cups of tea. While their friends are eating heavy lunches in front of the television my recruits will be breathing fresh air and having the time of their lives.'
Mr Tyler started the weekend and five-day survival courses 10 years ago. 'I found I had the skills to teach civilians as well as trained soldiers. I find it easy to communicate and get the best out of individuals,' he said.
Demand for courses that tested initiative and taught real-life survival skills was high - from both stressed individuals looking to throw their lives into perspective, and companies anxious to develop employees' team spirit.
'I've had a call yesterday from a doctor in Swansea who sounded like he'd really had enough. This morning a lad in business called. He said he'd been planning to spend Christmas Day sitting on a hill anyway and he might as well do it with me.'
Courses cost pounds 50 for the weekend. Women are particularly welcome. 'We cater for all levels. The women that do come often do better than the men. They can put up with the temperatures a lot easier - after all they have fat layers under the skin, don't they?' Mr Tyler said.