The Russian media have been reacting to the inquiry findings.

A Russia Today TV correspondent reporting from London on the Litvinenko inquiry says they are "very serious allegations, not worded too greatly... it seems to be lacking a lot of very hard evidence." 

In Sir Robert Owen's report, he makes a series of points about possible motives for Mr Litvinenko being killed:

• His work for British intelligence, criticism of the FSB and Mr Putin, and his association with other dissidents such as Boris Berezovsky
• There was also "undoubtedly a personal dimension to the antagonism" between Mr Putin and Litvinenko.
• Tensions dated back to their only face-to-face meeting in 1998, when Mr Putin was head of the FSB and Litvinenko wanted him to bring in reforms
• The dissident made "repeated highly personal attacks" on the president after seeking asylum in the UK in 2000, including an allegation of paedophilia in July 2006

Russia will not extradite the murder suspects, Andrei Lugovoi and Dmitry Kovtun, a "well-informed source in security services", has told Russian news agency Interax. 

There has been no official reaction to the Litvinenko inquiry so far.

BBC Montoring says that Interfax is quoting Andrei Lugovoi as saying: "The accusations against me are absurd.

"As we expected, there were no surprises. The results of the investigation made public today yet again confirm London's anti-Russian position, its blinkeredness and the unwillingness of the English to establish the true reason of Litvinenko's death."

Image source, AP

One of the men suspected of murdering Alexander Litvinenko, Andrei Lugovoi, has responded to the conclusions of the report, according to Russian news agency Interfax.

He says the accusations against him are "absurd", it reports.

Downing Street had no immediate comment on the report, but confirmed Home Secretary Theresa May would be giving the government's response in an oral statement to the House of Commons in the next few hours.

Moscow will reject the findings of the Litvinenko inquiry, claiming London "violated the principle of presuming innocence", Russian news agency RIA Novosti reports.

BBC correspondent Richard Galpin says there have been very significant statements coming out of the inquiry.

It has found the poisoning in London was carried out under the direction of Russia's FSB intelligence service. 

A number of reasons have been given for the assassination, including that after fleeing Russia, Mr Litvinenko made a series of very serious allegations against Russian President Vladimir Putin.

These include that he was a paedophile, which the Kremlin strongly denies, our correspondent says.

The FSB would have seen this as a "very serious betrayal", he said.

As well as following all the reaction as it comes in on this live page, you can also follow how the story unfolds during the day with our news story

Image source, AP

Mr Litvinenko's widow Marina said outside the High Court she was "very pleased that the words my husband spoke on his deathbed when he accused Mr Putin have been proved by an English court." 

Singling out then-FSB chief Nikolai Patrushev alongside Mr Putin, Sir Robert wrote: "Taking full account of all the evidence and analysis available to me, I find that the FSB operation to kill Litvinenko was probably approved by Mr Patrushev and also by President Putin." 

Sir Robert Owen's 300-page report says Andrei Lugovoi and Dmitri Kovtun were probably acting under the direction of Moscow's FSB intelligence service when they poisoned 43-year-old Mr Litvinenko with radioactive polonium 210 at the Millennium Hotel in Mayfair. 

Image source, AP

Judge Robert Owen points to a number of reasons why those within the Russian state would have targeted Litvinenko. 

These include his disclosures about FSB activity before he left Russia and his campaigning on sensitive issues in the UK, his conclusions state.

They also include his relationship with British intelligence and a "personal dimension" to the antagonism between Litvinenko and Vladimir Putin, the report says.

Litvinenko inquiry stronger than expected on Russian state responsibility - though some of most conclusive evidence may be secret, BBC security correspondent Gordon Corera says

"I find that the FSB (Russian Security Service) operation to kill Mr Litvinenko was probably approved by Mr Patrushev and also by President Putin" the report concludes. 

Litvinenko inquiry concludes former spy's killing an FSB operation probably approved by Vladimir Putin, BBC correspondent Gordon Carera says

The judge, Sir Robert Owen, heard from 62 witnesses in six months of hearings and was shown secret intelligence evidence about Mr Litvinenko and his links with British intelligence agencies.

The judge will decide whether to name anyone as having been responsible for Mr Litvinenko's death and whether any elements in the Russian state were responsible.

BBC security correspondent Gordon Corera says the real issue for the report is whether the trail leads to the heart of the Russian state and even to President Vladimir Putin himself.