A CONSERVATION charity is demanding to know what effects a barrage is likely to have on wildlife in the Severn Estuary.

The Royal Society for the Protection of Birds has said it wants to see the results of the government-led feasibility study into a Severn Tidal Power scheme.

Dr Mark Avery, the RSPB's director of conservation, said: "We know the Government have produced their own report on how a barrage would affect the tides and sediments of the Severn. The big questions now are what does that report say, why can't we see it?"

The request has been made after the conservation group gained access to an official report by the Dutch authorities into the risks and effects caused by the construction of a similar storm surge barrier across the Oosterschelde estuary in the Netherlands.

The report, written by the Dutch Ministry of Transport, Public Works and Water Management, found that since the barrage was built 20 years ago, salt marshes have disappeared, there has been a loss of mudflats along the estuary, a reduction in intertidal habitat such as shellfish and birds and tourism has suffered.

Dr Avery said: "This report makes grim reading. It is the closest we can get to proof that a barrage across the Severn will devastate the estuary.

"Although smaller, the Oosterschelde is very similar to the Severn Estuary in many ways and it is being damaged beyond repair, something our Government appears to have known since 2008.

"The Dutch built their barrier to prevent deadly storms from claiming lives. Ironically, it has now led to an increased risk of flooding behind the barrier, but it could be argued they had little choice at the time.

"On the Severn, we do have a choice. A barrage would not be built to stop storm surges but to harness the tides and generate electricity. There are other, far less environmentally damaging ways to do that, yet Government studies to date have been fixated on barrages."

The Department for Energy and Climate Change is currently researching the feasibility of a variety of methods of harnessing energy from the River Severn.

Options being considered include lagoons and smaller barrages but the most controversial suggestion is a 10-mile barrage between Somerset and Cardiff.

The government claims the larger £23 billion Severn Barrage project could generate up to five per cent of the UK's electricity.

A spokesman for the Department of Energy and Climate Change said it was considering parallels with the Dutch storm surge barrier as part of its two-year feasibility study currently being carried out into the tidal power project in the Severn Estuary.