Litvinenko's widow could boycott his inquest
The widow of poisoned ex-KGB spy Alexander Litvinenko could boycott his inquest if the government does not set up a public inquiry, her lawyer says.
At a pre-inquest hearing, her barrister called for the inquest process to be halted until a decision is made.
The coroner in charge of the inquest has requested a public inquiry instead.
It follows his previous ruling that he could not hear evidence in public linked to alleged Russian state involvement.
A public inquiry would allow some evidence to be heard in secret.
At the hearing at the High Court, coroner Sir Robert Owen said he had written to the Lord Chancellor asking him to decide if there should be a public inquiry instead of an inquest as a matter of urgency.
Mr Litvinenko, 43, died after he was poisoned with radioactive polonium-210 while drinking tea at London hotel in 2006.
Mrs Litvinenko's barrister Ben Emmerson QC accused the government of trying to "get her to abandon her attempt to get at the truth" and called for the inquest process to be halted until the government announces its decision.
"We are at a loss to see a good-faith reason to prevent a hearing which could get at the truth from going ahead," he said.
"The inquest should now stand adjourned. There should be a full stop at the inquest until the matter is resolved."
The family believe Mr Litvinenko was working for MI6 at the time of his death and was killed on the orders of the Kremlin.
Mrs Litvinenko has said a public inquiry is the only way to find the truth about the death of her husband.
Mr Emmerson also told the hearing that a ministerial aide to Foreign Office minister David Lidington had made a "direct approach" to Mrs Litvinenko,
The aide phoned her last month to arrange a call between them while Prime Minister David Cameron was having talks with the Russian President Vladimir Putin.
But Mr Lidington had not called because the talks in Russia had not moved beyond unrelated security issues and the Syrian conflict.
Mr Emmerson described it as "quite improper" for a minister from a department involved in the inquest to contact her without the knowledge of her legal team.
Sir Robert replied: "I have to say I am astonished."
Representing the government, Neil Garnham QC said there was "nothing improper about the phone call" and it was "a matter of common courtesy" that the minister would have informed Mrs Litvinenko of the talks before they were in the press.
He added that a decision on holding a public inquiry would be made "as quickly as possible" by the Home Office.
The inquest into Mr Litvinenko's 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 Lugovoy and Dmitri Kovtun - but the Russian authorities have refused to hand them over. They deny any involvement.
The hearing was adjourned to a date to be fixed.