“You might think a 500-metre stretch of wall is a bit boring, but it’s not,” he said. “You’re working with a natural medium and no two stones are ever the same. Another bonus is that you get the chance to go into some lovely properties and gardens to which you wouldn’t normally get access.”

The Cotswolds has hundreds of miles of stone walls, and many fine stone houses with walled gardens. Richard Ingles is never short of work. He estimates that using new stone, he can build three metres of wall a day. And charging pound;50 per metre, he can make a good living.

Richard, 58, from Broadway, Worcestershire, took up dry-stone walling after he was made redundant from the National Trust in the mid-1980s.

He grew up in farming and had some experience of fixing walls. But he decided to become properly qualified and took the Dry-Stone Walling Association’s craftsman certification scheme.

The scheme is rigorous, designed to ensure trainees reach the highest standards. There are four levels, from initial to master craftsman, with examinations at each step.

With his previous experience of walling, Richard Ingles became a master craftsman within 18 months. But often it can take years to reach that standard. And increasingly many in his trade are setting themselves up as professional dry-stone wallers without being properly qualified.

“You get people who say I have been on a course, but they really haven’t been taught correctly,” he said. “This is why the association brought in these examinations. A lot of work has gone into it and rightly so.”

There are some 112,000 kilometres of dry stone walls in England, according to the Countryside Agency, but they’re crumbling away. Some 70 per cent are in need of repair.

Meanwhile training in this ancient crat is in chaos, says the Dry Stone Walling Association. Government grants are available to help repair stone walls, but according to the association’s chairman, Paul Webley: “If you put money into a thing, you need to have a suitably trained workforce to take on the projects that you’re doing, rather than people coming in who are unskilled.

“You find that work is being done very quickly in order to earn enough money. You could then end up doing a lot of walling that may only have a very short life.

“Some of these walls have had 100 to 150-year life spans. If you put up walls quickly and without a lot of training and care, in 20 years they’ll be back in the same condition.”

Webley is a retired rural studies teacher from Slaithwaite, West Yorkshire, who has been dry-stone walling since 1980.

He said although walling is taught in a number of colleges, it is often only as recreational weekend courses or merely as part of other subjects.

“There are a few training agencies running ad hoc schemes, but there’s no suitable NVQ at the end of the day,” he said.

“There’s very little co-ordination of training. Most people getting into the craft are either virtually self-taught. Or they come off training schemes and the training they have received is very hit and miss, depending on who their instructor was.”

The answer, he believes, lies in setting up a nationally recognised training scheme. The association is currently lobbying the Ministry of Agriculture, Fisheries amp; Food for funds.

“I don’t think you ever stop learning,” he said. “You can’t stop learning - every wall is different, every site is different, every time you put on a stone you solve a problem and then create another because the stone isn’t regular.

“It’s not a craft that you can do automatically. If your brain switches off you might as well stick your hammer in your bag and go home.”

For further information, contact the Dry Stone Walling Association of Great Britain, PO Box 8615, Sutton Coldfield, B75 7HQ, tel 0121 378 0493