The last photo taken of poisoned spy Alexander Litvinenko alive

A British investigation into the fatal poisoning of former KGB agent Alexander Litvinenko is set to be published on Thursday.

Almost a decade after Alexander Litvinenko's fatal poisoning sparked one of Britain's most extraordinary murder investigations, the conclusions of an official inquiry into his death are set to be published.

Chairman Sir Robert Owen's report will be published on Thursday, just under a year after the probe opened.

The inquiry was tasked with identifying where responsibility for Mr Litvinenko's death lies. Sir Robert is expected to set out "appropriate recommendations" in his report, but he cannot make any findings of civil or criminal liability, nor award any compensation.

Mr Litvinenko, a former KGB agent, died in November 2006 aged 43 after drinking tea laced with radioactive polonium in a London hotel.

Police concluded that the fatal dose was probably consumed during a meeting with Dmitri Kovtun and Andrei Lugovoi at a hotel in central London.

In the years that followed, the case attracted an avalanche of claims and theories and threatened to plunge Anglo-Russian relations into crisis.

Last year, the events were examined in forensic detail by the inquiry, convened following a long legal battle by Mr Litvinenko's widow Marina.

During six months of hearings, dozens of witnesses gave evidence and a huge number of documents were examined.

The killing was described as a "nuclear attack" on the streets of London, and some of the testimony at the inquiry was highly technical.

A Home Office pathologist described the post-mortem examination of the poisoned spy as"one of the most dangerous ever undertaken in the western world", while the inquiry heard about a trail of radioactive traces found in locations around London.

Much focus will fall this week on the report's conclusions regarding allegations that the Russian state was behind the murder.

On his deathbed, Mr Litvinenko pointed the finger at Russian president Vladimir Putin. The Kremlin has always denied the claims.

In his closing speech, Ben Emmerson QC, representing Mr Litvinenko's widow and son Anatoly, said: "When all of this evidence is viewed in the round as it must be, it establishes Russian state responsibility for Mr Litvinenko's murder beyond reasonable doubt, and if the Russian state is responsible, Vladimir Putin is responsible."

The world of espionage also featured heavily during the hearings.

Mr Litvinenko started working with MI6 in 2003, three years after he first arrived in Britain, and had a handler called "Martin" who arranged payments to his account for consultancy work about Russian organised crime, the inquiry heard.

Kovtun and Lugovoi were identified as the prime suspects in the murder but attempts to extradite them have failed. Both deny involvement.

Richard Horwell QC, for Scotland Yard, said the claim that they were framed by the MI6 "does not bear scrutiny".

He dismissed claims Mr Litvinenko was involved in the polonium trade and said the suggestion of suicide was a "spiteful and insensitive accusation" that should also be rejected.

As of November, the inquiry had cost £2.2 million.

Belfast Telegraph