CEFAS has insisted the study estimated to cost £9 million is necessary, despite many environmental organisations criticising the value of the two-year investigation.

Ted Potter of CEFAS’ freshwater team, said: “Determining whether the scheme may be a threat is very complex; what is detrimental for one species might be beneficial for another.”

“The barrage would affect every species in a different way, so every case must be studied and fully assessed in order to make an overall decision,” added Potter.

The Severn Estuary is Europe’s largest fishery with huge quantities of freshwater fish, including salmon, all of which environmental groups believe would suffer if the project goes ahead.

Director of the Salmon and Trout Association, Paul Knight, said: “The salmon, sea trout and many species of sea fish, whose habitat is in the Severn Estuary, would be severely impacted if the barrage were to be built."

 

 

Save the Severn campaign leader Stuart Ballard doesn't believe the government's study can be balanced.

 

Barrage can meet renewable targets