A group of students contemplates a small engineering challenge: on the right there lies a ruined, crumbling old Cotswold stone wall worn down by years of rain and frost damage. To the left are yards of neat, new drystone wall. This group of eight - none of whom would know a coping stone from a chrysanthemum - has to turn right into left.

“We have made it easy for you,” says instructor Jonathan Bendle, surveying the foundation trench already dug out. “The main thing is we’re not worried about speed - we just want quality.” He runs through the whole process, making the ancient craft of drystone walling sound relatively simple. But then he has had 14 years practice.

The lesson begins with stripping the old wall out and learning about its structure. This is the wall’s secret: solid foundations, tight outer layers of facing stones, packing inside and coping stones on the top. Some of these walls around the Cotswolds were so well-built they have lasted centuries. It is, says our tutor, all about using the right techniques.

Beginning with big, flat foundation stones, work begins on the new wall. It’s almost like a big jigsaw puzzle, trying to find the right piece for the right space. But here if a stone doesn’t fit, you can cut it with a bricking hammer. Soon the first layers of wall are rising out of the ground, flat, tightly-packed facing stones on front and back, and smaller stone infill in the middle.

Drystone walling is becoming increasingly popular says Jona-than Bendle. “Every year we have increased the number of courses. People realise the Cotswolds is a big tourist attraction because of the stone and I think that creates an interest in walling.”

One student, Stephen Langton, has come to learn walling to help him renovate an old wool merchant’s house. “It’s a real art isn’t it,” he says. “I shall be doing this for several years I should think.”

Martin Whittaker This drystone walling introduction course took place at the Centre for Agriculture and Rural Skills, run by the Royal Agricultural College,Cirencester, Gloucestershire GL7 6JS Tel: 01285 652531