COUNTRYSIDE around Swindon has become a haven for rare wild flowers. At a time when native flowers are under attack from weeds, herbicides, rising traffic pollution and aggressive introduced plants, there are pockets of land on our doorstep where they are allowed to thrive.

The New Atlas of the British and Irish Flora highlights the situation in its new survey, which has been carried out by a team of 1,600 botanists.

It says Wiltshire is one of the counties where some wild flowers are threatened but other rare species are surviving in the county better than anywhere else in the UK.

The new census, the first undertaken in 40 years, shows that nationally many indigenous species are threatened with extinction.

It also names the richest 10 kilometre-square site studied in England as around the Dorset town of Wareham which is home to 884 species.

Throughout the whole of Wiltshire 1,200 wild flowers have been recorded. In parts of the north of the county the grasslands are some of the best for wild flowers and plants in the country.

The former airfield at Blakehill near Cricklade which will shortly be open to the public is being turned into a reserve by Wiltshire Wildlife Trust and is rich in wildflowers.

And at nearby North Meadow the rare snake's-head fritillary attracts hundreds of visitors every year when it blooms. Other rare wildflowers growing in Wiltshire include the adders tongue fern and the downy-fruited sedge.

On the county's arable farm land the corn flower, the corn buttercup, the dense flowered fumitory, the venus looking glass and the weasel's snout are all in decline.

Wiltshire Wildlife Trust spokes-woman Sharon Charity said: "Where these species are found a lot of work is going on with the farmers to manage their land to help these flowers."

Nationally the botanists have identified the burnt orchid as among the most seriously threatened, along with grassland species such as the carline thistle, the purple milkvetch and the slender bedstraw.

Chris Preston, one of the editors of the atlas, said: "We are losing some species native to this country and that is a serious worry. The biggest and most intractable problem is the increase of nutrient levels in the countryside."

Secretary of State for Rural Affairs, Margaret Beckett, said the publication would act as a standard to judge the success or failure of policies to protect the environment for years to come.