ROOFTOPS in the Dales are being spoiled forever because foreign imports are being used through a lack of local resources, a national park report says.

A meeting of the Yorkshire Dales National Park Authority this week heard that Hill Top Quarry, near Keld, is the only producer of natural sandstone roofing flags within the park.

And, although the quarry has recently been given permission to increase extraction, its total output of new roofing materials equates to just 900 square metres of roof per year.

The report by Paul Collins, barns and walls conservation officer, presented worrying details of the potential change to the Dales landscape, particularly through the availability of imported flags from India which had found their way to the area.

The report said: "The vernacular stone roof coverings of the Yorkshire Dales are a fundamental component of the built heritage and a distinctive characteristic of the historic landscape.

"However, the limited availability of new and reclaimed roofing flags and slate has resulted in the replacement of stone roofs with cheaper substitute materials that have little to do with local building traditions. This incremental change is affecting the character of the landscape."

The quarrying and mining of stone for roofing in England is an ancient activity that dates back to Roman times.

Since the 17th century, millstone grits and carboniferous sandstone flags from the Yoredale Series have been the most commonly used roofing materials in the Yorkshire Dales although are not in geological terms "true" slates.

A few small outcrops of older roofing stone was used within the park at Helwith Bridge and Ingleton.

Substitute materials such as artificial tiles are cheaper and widely available but, according to the park, do nothing to enhance the outlook, being a different colour and a random size.

In addition, natural sandstone flags have been imported from India.

Mr Collins' report said there were a number a reasons why the use of these imported flags should be resisted. One was that no one knew how durable they were, how they would weather on a roof and if lichen would colonise.

He also said they were sawn to thickness, not split, were very bland, and lacked texture.

For a long time the shortage of traditional stone roofing flags has been recognised as a problem by the authority.

A detailed grant-assisted study was commissioned in 1989 to investigate the feasibility of re-opening one or more small quarries or mines in or adjacent to the national park.

It looked at Richmondshire and found six out of 51 were promising. However, more investigation was needed to look at workability, quantity and quality of the stone deposits at each of these sites.

Park members voted to approve a series of actions including:

o seeking an approved list of local stone roofing slate suppliers for inclusion in the forthcoming design guide;

o to reserve the right to refuse the use of imported Indian stone roofing flags in any future national park-funded conservation grant scheme;

o to seek agreement with funding agencies to award 100 per cent grant assistance towards the difference in material costs between new, locally produced, natural stone roofing flags and reclaimed slates in any future conservation grant scheme;

o to investigate funding sources for research into local variation and distribution of roofing materials and types in the park, and opportunities in establishing new stone slate production.