A Herefordshire farm once saved from ruin by the Prince of Wales faces a new threat with the installation of a giant gas pipe across the county's Golden Valley.

Transco's plans to install the pipe across farmland in what is considered to be one of the most beautiful parts of Britain have been condemned by critics as "environmental illiteracy".

The route is expected to go through Turnastone Court Farm in Vowchurch, provoking fears that its nationally important water meadows, left unploughed for 400 years, will be devastated.

The 247-acre farm was bought for £1.5 million by the Countryside Restoration Trust in 2000 after a undisclosed donation from Prince Charles to save the water meadows.

Now tenants Robert and Chrissie Fraser fear Transco will cut a 150ft wide swathe through the land, destroying the meadows and disturbing wildlife.

Mr Fraser said: "We have tried so hard to maintain and improve the wildlife habitats on the farm and it would be awful to see that work undone.

"Some of these beautiful meadows have remained unploughed for more than 400 years, and that includes the Dig For Victory campaign during the last war.

"We are determined to save these species-rich meadows that include Trench Royal, a three-mile long irrigation channel completed during the 17th Century which is an integral part of Herefordshire's agricultural heritage."

Robin Page, chairman of the Countryside Restoration Trust, said: "This whole act of environmental illiteracy is made worse by the fact that Transco want its pipeline to pass through one of the most beautiful and unspoilt valleys in Britain.

"The pipeline will dissect ancient grazing land, threaten the water table and hydrology of Britain's most ancient water meadows, damage important archaeological remains and compromise some of Britain's most threatened fauna and flora - it is almost beyond belief." The meadows are the remnants of a project set up in the River Dore valley by Rowland Vaughan.

The 16th and 17th century earthworks were part of a scientific irrigation of part of the Golden Valley between Peterchurch and Newcourt by the colony set up by Vaughan.

These included Trench Royal, nearly three miles long, 10ft wide and 4ft deep.

Transco is expected to announce the specific route the pipeline will take across 184 km of Herefordshire and Gloucestershire shortly, although Mr Fraser said he had seen a copy showing his farm was featured in the plans.

Intended to meet a rising national demand, gas from abroad will be landed at Milford Haven and then piped through Transco's national grid to Gloucestershire.

Transco spokeswoman Caroline Davidson said: "We fully appreciate the sensitivities of the agricultural community and as soon as we know the exact route we will be discussing it with those affected.

"Care for the environment is of upmost importance."

The Country Land and Business Association is in negotiations with Transco in a bid to safeguard farmers and landowners rights and to ensure compensation.

David Price, CLA assistant regional director, said the pipeline was due to be constructed in a very short timescale - within the next two years - for which affected farmers and landowners needed to be well prepared."