Litvinenko widow in legal bid for public inquiry
The widow of poisoned ex-KGB spy Alexander Litvinenko has gone to court to challenge the UK's refusal to hold a public inquiry into his death.
But judges refused Marina Litvinenko an order restricting her liability for costs if she loses the case.
Mr Litvinenko was poisoned with radioactive polonium in London in 2006.
The government ruled out an inquiry despite the coroner's decision that the inquest could not hear evidence of alleged Russian state involvement.
Coroner Sir Robert Owen had requested an inquiry after ruling the inquest could not discuss Russia's alleged role in the death, but in May the government refused, saying the inquest would be an effective investigation into the death.
Mr Litvinenko, 43, died after he was poisoned with radioactive polonium while drinking tea with two Russian men, one a former KGB officer, at a London hotel in 2006.
His family believe he was working for MI6 at the time of his death and was killed on the orders of the Kremlin.
The inquest into his death has already faced major delays because both the UK and Russian governments have been slow to disclose documents.
Police have sought the arrest of two Russian nationals in relation to the death, Andrei Lugovoi and Dmitri Kovtun, both of whom deny any involvement. The Russian authorities have rejected requests to extradite the two men.
After the government turned down the request for a public inquiry, Mrs Litvinenko said she and her legal team were "shocked and disappointed".
Her lawyers are asking three judges at London's High Court - Lord Justice Goldring, Lord Justice Treacy and Mr Justice Mitting - for permission to challenge the legality of the government's decision in an application for judicial review.
Ben Emerson QC, appearing for Mrs Litvinenko, asked that her costs be protected, saying if her challenge went ahead it could lead to a £40,000 legal bill if she were unsuccessful - almost "everything she has in terms of assets she can access".
He argued there was no-one else to bring the challenge, which was of national and international importance, and described the death as "an act of nuclear terrorism on the streets of London".
The judges said they would give their reasons for refusing the protected costs order on Friday.
The question of whether Mrs Litvinenko should be given the go-ahead to challenge Home Secretary Theresa May's decision refusing an immediate inquiry is also to be dealt with by judges at a further hearing.
At the request of the government, Sir Robert previously agreed to exclude certain material from his inquest on the grounds its disclosure could be damaging to national security.
This meant the inquest would be unable to look at whether the Russian state was behind the killing or whether the British state could have done more to protect Mr Litvinenko.
In June, Sir Robert wrote to the justice secretary to request a public inquiry instead of an inquest.
Refusing the request in July, Home Secretary Theresa May said UK-Russian relations played a role in the decision but there were other factors such as cost and duration.