Families worried about plans for more than 800 new homes on woodlands on the edge of Norwich have welcomed news that part of the site has been designated as ancient woodland.

The Friends of Thorpe Woodlands are delighted by the announcement from Natural England, the government's official advisory body on ecological and environmental issues, that 32 acres of Thorpe Woods have been officially designated as ancient woodland.

The area falls within the Racecourse Plantation, between Salhouse Road and Plumstead Road East, and is clearly identified as woodland in maps dating from 1837 and there is also evidence for woodland on this site going back to the Domesday Book.

The total number of plant species found in Racecourse Plantation is thought to exceed 250, making the site among the most botanically rich in Norfolk.

Ancient Woodland is defined as woodland on land that has been continuously wooded since 1600.

The announcement follows many months of work by John Allaway, an arboricultural consultant and contractor, who has played a key role in the Friends of Thorpe Woodlands since its conception.

He was helped by botanist Shane Plant and landscape historians Kate Scrivener and Jo Yates.

Mr Allaway, who lives in Drayton, said: 'I became interested in the these woods when I attended a meeting held by the landowners last year, at which they described them as little more than overgrown conifer plantations which they needed to find alternative uses for.

'The following day I visited Racecourse Plantation and couldn't believe my eyes.

'The quality of the habitat is stunning, and I noticed several indications that the site may have been ancient woodland prior to it being turned into a plantation.'

Lorna Beckett, chairman of the friends, said: 'This is wonderful news. I know I speak for all the hundreds of local people who make up the friends when I say how delighted we are that these beautiful woodlands, treasured by so many, are at last being recognized for their great age and importance. We are indebted to John Allaway for his magnificent work and commitment to saving these precious woods'.

The friends were set up over a year ago, after the owners of the woods, the Thorpe and Felthorpe Trust, announced plans to build more than 800 houses.

The woods fall within Broadland District Council's development triangle and over the next few months the council will decide whether the woods should be identified as a green space within that development area or not.

The inclusion of the eastern section of the wood means that it will benefit from enhanced protection. Broadland District Council has strong policies protecting ancient woodlands, and the Norfolk Biodiversity Action Plan, administered by Norfolk County Council, states that there should be no loss of ancient woodland.

A spokesman for Broadland District Council said: 'Racecourse Plantation is already designated as a County Wildlife Site and an area of Landscape Value. Broadland council has always recognised just how important areas like this are when planning for the future, and its partial designation as Ancient Woodland will be another key factor to be taken into account as decisions are made about the character of development within the Growth Triangle. Our whole aim is to be sensitive to the historic and natural heritage and to fuse that with the 21st century need for new homes and jobs as we continue to plan ahead.'

John Hiskett, of Norfolk Wildlife Trust, said: 'Due to its size and location adjacent to other County Wildlife Sites, Racecourse Plantation forms a key link in the green infrastructure of north east Norwich and the retention of the whole area as natural green space will be especially important in the light of large scale housing proposals for the north east Norwich growth triangle.'

Information on the Thorpe woods and the campaign to save them can be found at www.savethorpewoodlands.blogspot.com