Jobs and investment could be lost unless the Government urgently addresses the implications of Brexit for the civil nuclear industry, a union is warning.
Prospect, which represents engineers and specialists, called for a new independent body to be established to develop the sector and help British firms competing for contracts abroad.
The trade union has warned that the Government has not properly addressed what the impact of Brexit will be for Cumbria's proposed nuclear new build in Moorside, near Sellafield.
When Britain leaves the EU it will also leave Euratom, the European Atomic Energy Community, responsible for nuclear safety and security in Europe since 1957. Last week's Queen's Speech announced a Nuclear Safeguards Bill to create a new regime for nuclear regulation and safeguards but the union has claimed this is not enough.
Estimates suggest the global market for new nuclear projects and decommissioning over the next decade could be worth almost £1 trillion, with the market for new small modular reactors worth £250bn-£400bn, said the union.
General secretary Mike Clancy said: "Britain is a world leader in nuclear engineering, research and decommissioning, yet we risk losing out as uncertainty and Brexit hit the industry.
"We need clear leadership from government to get British nuclear back on track, helping to deliver new nuclear power generation, supporting innovation and creating more high-skilled jobs.
"The Nuclear Safeguards bill announced in the Queen's Speech fails to address the risk to jobs from leaving Euratom or concerns about new power stations at Hinkley Point C or Moorside in Cumbria.
"That's why we are calling for a new independent nuclear champion to advocate for the industry at home and abroad. In these uncertain times a properly resourced champion could put paid to uncertainty over nuclear, instead transforming the industry into an engine for jobs, growth and economic success."
A Business Department spokesman said: "In last week's Queen's Speech, this Government made clear our commitment to establishing a UK nuclear safeguards regime as we leave the European Union and Euratom.
"There will be no immediate changes to the UK's safeguards arrangements, the exact details of which will be subject to detailed consultation with the regulator, industry and international partners."
Earlier this year Copeland MP Trudy Harrison suggested a UK-only successor to Euratom could be based in her constituency.
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