Greenpeace said it has filed a request for a judicial review of the 680 million pound ($1.06 billion) aid package that the government has provided to keep the provider of up to a quarter of the UK's power from going bust."We are going to court to get this handout paid back to the public purse," said Greenpeace campaigner Rick Le Coyte, calling nuclear power "dangerous and expensive energy we don't need".
A High Court official confirmed receiving a filing from Greenpeace this week, but was unable to give any details.
Loss-making British Energy went to the government for help a month ago. UK power prices have fallen to below the cost of production for its reactors, and show few signs of recovering.
Greenpeace said it had brought the action with renewable energy provider Ecotricity. The pair have already written to the government protesting at the temporary aid package which matures at the end of November.
Some analysts say the UK cannot do without the nuclear element of its power mix, but anti-nuclear groups say the gap can and should be filled by renewable providers such as wind turbines favoured by Ecotricity.