Plans for the construction of a barrage across the Severn Estuary would have "disastrous effects" on wildlife and tourism, according to the Royal Society for the Protection of Birds (RSPB).

The conservation charity has claimed that a Dutch study into the impact of the storm surge barrier built across the Oosterschelde estuary during the 1980s outlines consequences that could also affect the Severn Estuary. Increased erosion has led to a decrease in the number of mudflats along the Oosterschelde estuary, which has led to higher water levels and will mean that more money will need to be invested in stronger sea defences.

The report also found that shellfish and bird species could see numbers fall by up to 80 per cent as less intertidal habitats become available, which is set to have a knock-on effect on tourism. Dr Mark Avery, the RSPB's director of conservation, 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.

"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."