RSPB officials have expressed dismay at the government's decision to back the potential Sizewell C nuclear plant with £100million of funding.
The proposed twin reactor development would be built next to Sizewell B, close to the RSPB Minsmere nature reserve.
The RSPB and the Suffolk Wildlife Trust have long been opposed to the development because they say it will lead to a large loss of habitat for animals and could see millions of dead fish pumped into the sea each year.
EDF has always maintained that the power station would help biodiversity by helping to tackle climate change.
A spokesperson for the RSPB said: "The RSPB is shocked to hear that the government will be investing £100million of tax payer's money in Sizewell C before a decision has been made to build it. The government claim to want to be a world leader in their response to the nature crisis. That’s a great ambition, but it is utterly incompatible with throwing £100m at a development that could have catastrophic impacts on nature.
“The RSPB, other charities and organisations have just spent a gruelling six months engaging with the Planning Inspectorate’s examination process, expected to report next month. We trust that the Secretary of State will follow the Planning Inspectorate’s advice before making a final decision on Sizewell C.
“RSPB Minsmere is incredibly important for both people and wildlife. Over 104,000 people have taken action to show that they Love Minsmere and to say that Sizewell C must not go ahead given its potential environmental impacts."
Alison Downes, of Stop Sizewell C, said: "This cash injection seems be an attempt to shore up confidence in Sizewell C, for if investors were enthusiastic about the project, why would taxpayers' money be needed at this time?
"It also tells us that there is a long way to go before a Final Investment Decision will be reached - it certainly won't be this summer as EDF wished.
"We still don't understand government's interest in large-scale nuclear, which can't beat renewables on cost or time to save the climate and is very risky, especially when - like Sizewell C - it is proposed in such a damaging location."
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