The findings of the inquiry into former Russian spy Alexander Litvinenko's death will be revealed, nearly a decade after his fatal poisoning sparked an extraordinary murder inquiry.
Chairman Sir Robert Owen's report will be published in Parliament on Thursday, just under a year after the probe's public opening.
The inquiry was tasked with identifying where responsibility for Mr Litvinenko's death lies.
Sir Robert is expected to set out "appropriate recommendations", but he cannot make any findings of civil or criminal liability, nor award any compensation.
Mr Litvinenko, a former KGB agent who left Russia and claimed asylum in the UK in 2000, died in November 2006 aged 43 after drinking tea laced with radioactive polonium in a London hotel.
Police concluded the fatal dose was probably consumed during a meeting with Dmitri Kovtun and Andrei Lugovoi, who were identified as prime suspects.
However, attempts to extradite the pair, who both deny involvement, have failed.
In the years that followed Mr Litvinenko's death, the case attracted an avalanche of claims and theories and threatened to plunge Anglo-Russian relations into crisis.
Much focus will fall on the report's conclusions regarding allegations that the Russian state was involved in the murder.
On his deathbed, Mr Litvinenko accused Russian president Vladimir Putin of ordering his assassination - an allegation the Kremlin denies.
The inquiry, convened following a long legal battle by Mr Litvinenko's widow Marina, took evidence from dozens of witnesses and examined a huge number of documents.
As of November, it had cost £2.2 million.