A wetland restoration project praised by wildlife guru David Bellamy is facing a major setback after suffering a spate of sabotage attacks costing tens of thousands of pounds.

The ambitious plans to turn farmland back into marshland near Upton-on-Severn, Worcestershire, have been beset with problems since work began five years ago.

But volunteers at Longdon Marsh have now been forced to delay the project for another year after rainwater collected to flood the fields was drained off and the water pumps stolen.

Worcestershire Wildlife Trust, which owns the 120-acre site, said it had suffered a number of vandalism attacks from saboteurs desperate to ensure the project does not get off the ground.

John Hodson, conservation officer for the trust, said: "It is clear that someone is attempting to sabotage the restoration of this wetland reserve.

"While this vandalism is dispiriting, it will not affect our aim to create a tremendous asset for wildlife, local people and visitors."

Kate Thomas, marketing manager, added: "We were at the crucial stage being at the end of a five-year project. This winter was the first time we had water collected, which would have been used to wet the site, and the vandals have hit right at the time it was coming to fruition so it is going to set us back.

"The large amount of water we should have collected from rainfall has all been let out and so we are now looking at another 12 months' work.

"We are well aware people could have concerns and we wanted to be totally upfront and explain to the local community what we were doing.

"We have had very little other than positive feedback and everybody understands what we are doing is not going to be flooding anybody else's land or affecting the water course."

The trust bought Hill Court Farm and The Backlands in 2001 with a grant of £803,500 from the Heritage Lottery Fund.

Attacks began in June last year, shortly before David Bellamy visited the site to celebrate the completion of on-site works.

Pumping equipment was damaged, a contractors' caravan was burned down, inspection chambers were made unsafe, and gates were lifted off their hinges.

This winter, valves controlling the water collection and flow have been opened on a regular basis to release stored water to escape from the site.

Staff repaired the damage each time, but in the latest act the main control structures were unbolted and stolen.

The wetland project was launched in a bid to bring back some of the marshes lost more than 100 years ago when land was drained for farming.

Longdon and adjoining Eldersfield Marsh are an integral part of the historic landscape and once formed Worcestershire's largest and most important wetland. Before draining took place, 20 per cent of Worcestershire supported wetland habitats. Now just one per cent remains.

The trust said more than a quarter of British wildlife relied on wetland habitats for survival and the project would attract a range of wading birds, wildfowl and rare plants.

Rob Williams, the chairman of the Severn and Avon Vales Wetland Partnership, condemned the vandalism.

"We firmly believe the restoration of wetland habitats on Longdon Marsh and other areas along the River Severn floodplain can generate environmental and economic benefits for local communities as well as wildlife," he said.

"Vandalism such as this not only damages wildlife but also undermines the opportunities for developing wider socioeconomic benefits." ..SUPL: