The government is drawing up plans to replicate the benefits of remaining a member of the Euratom treaty, which governs the movement of nuclear materials across Europe, in the face of a growing rebellion of Conservative MPs.

The Guardian understands that one option being considered is an “associate membership”, similar to that held by Switzerland, or paying money to an international agency to set up an independent arrangement.

Nine Tory MPs signalled that they could line up with Labour and the Liberal Democrats on the issue, making it difficult for May to secure a parliamentary majority.

Ed Vaizey, a former Tory minister, joined forces with Labour MP Rachel Reeves over the weekend to warn that the treaty was vital to protect the nuclear power industry in the UK.

Q&A What is at risk if the UK quits Euratom? Show Scientists have warned that British power stations may not be able to source nuclear fuel if it cannot be legally transported across borders. The shipment of medical isotopes used in scans and cancer treatment is also said to be jeopardised. European workers on shared research projects, such as experimental fusion reactors, face an equally uncertain future without Euratom’s separate guarantees of freedom of movement. Arranging new rules to ensure safety and govern shipments should not be that hard; but the cost of any short-term chaos is hard to justify given that nobody ever complained about the minor compromises imposed by Euratom on British sovereignty in the first place.

It comes after a warning that cancer patients could be at risk if the government fails to stay part of the group, the European atomic energy community.

Dr Nicola Strickland, president of the Royal College of Radiologists, told the Evening Standard she feared the risk of “Brexatom” could threaten the supply of radioactive isotopes, used in scans and treatment.

The newspaper, edited by the former chancellor George Osborne, carried a story on its front page with the headline: “Cancer patients in Brexit scare.”

The pressure has been mounting since May included leaving Euratom in her article 50 letter to the European council president, Donald Tusk.

Critics believe May has created the problem by insisting that the UK cannot remain under the jurisdiction of the European court of justice.

However, a senior Whitehall source told the Guardian that the government had included that line because of a belief that the UK had no choice. They said that “both the UK government and the European commission thought it was a legal necessity” to leave Euratom as part of Brexit.

However, they said significant work was under way to ensure that Britain had the “same outcomes” as currently enjoyed within the grouping, and admitted that country membership was being considered.

“We will not be marking our own homework when it comes to nuclear safety,” he added.



A source from the European commission confirmed that, legally speaking, the UK would have to leave Euratom as part of Brexit.

All the members of Euratom are inside the EU, but Switzerland is an equal partner through associate membership.

Reeves, who is running to become chair of the business select committee in parliament, said: “MPs from across the political spectrum are clearly very worried about the prospect of leaving Euratom and ideology getting ahead of sensible politics.

“It is time for the government to rethink this. Nobody voted to leave the EU to come out of Euratom, and no one would think the government was going soft on Brexit if they rowed back on this.”

Dame Sue Ion, honorary president of the Nuclear Skills Academy and former chair of the Nuclear Innovation Research Advisory Board, said: “Associate membership is better than nothing, but it all depends on exactly what that means. It’s normally associated with access to Euratom research, not the wider cover provided by the treaty for everything else [such as transport of nuclear materials].”

She added: “The best option is clearly to stay in, which is entirely possible.”

Unions urged ministers to listen to their MPs and change their mind on quitting Euratom.

Mike Clancy, general secretary of Prospect, said: “It is now clear that a hasty retreat from Euratom would be damaging to the UK. The risks to the NHS, British nuclear sector and high-skilled jobs in the industry are too great for the government to get this wrong.”

At a recent industry conference, Lord Hutton, chair of the Nuclear Industry Association, said he still held out hope that the government could reconsider leaving Euratom entirely.

If the UK was to leave without new arrangements or a transitional arrangement in place, he warned: “There is real concern that the economic growth potential of the UK’s nuclear programme might be damaged. We mustn’t let that happen.”