A TOTAL of 237 kilometres of dry stone walls - equal to twice the length of Hadrian's Wall - have been restored in the Yorkshire dales since 1992 with help from the Ministry of Agriculture's environmentally sensitive area scheme.

Regarded by many as the "fingerprint" of the Yorkshire dales, many of these distinctive field boundaries, along with their associated small field barns, have fallen into disuse as farming practices have changed. Since 1992, 350 barns have also been restored.

The Ministry established the Pennine dales ESA in 1987. It has since been expanded to cover 215 square miles of North Yorkshire, Durham, Cumbria and Northumberland.

Within the ESA, MAFF offers grants to farmers to preserve herb-rich meadows and pasture, and to restore traditional farm buildings, stone walls, hedges and semi-natural habitats.

MAFF makes available up to 80pc of the cost of wall restoration work, with the agreement holder paying the remainder.

The cost of walling varies significantly. In the higher and more remote northern dales like Teesdale, a typical rate is £14 a metre. Further south the price rises and in somewhere like Grassington, close to the Leeds conurbation, about £28 a metre, similar to rates charged by building contractors, is not uncommon.

Mr Martin O'Hanlon, MAFF's senior Pennine dales ESA project officer, said a good stonewaller could build five metres of wall a day, providing the weather was not too bad.

"By helping farmers to restore these traditional features we are preserving the historic landscape, he said. "At the same time, we're also making the fields stockproof and offering protection to animals during winter. The aim of the scheme is to achieve environmental benefits over and above what good farming practice will achieve.

"It is also preserving traditional skills and supporting the local economy. The ESA alone provides enough work to keep at least 25 dry stone wallers busy.