Newspaper headlines: Focus on Litvinenko murder findings
The findings - and the fallout - from the inquiry into the murder of former Russian spy Alexander Litvinenko is the main story for the press.
Sir Robert Owen's report said Russian President Vladimir Putin "probably" approved the killing of Mr Litvinenko who was poisoned with tea laced with radioactive polonium-210 in London in 2006.
The Guardian reflects the view in many of the papers that action should be taken against Russia following the outcome of the inquiry.
The paper says the report was more critical than expected - and Mr Litvinenko's widow Marina said it would be "unthinkable" for the UK government to ignore its findings.
The Guardian states: "Owen concluded that two Russian killers - Dmitry Kovtun and Andrei Lugovoi - had carried out the murder 'under the direction' of Russia's FSB spy agency."
Home Secretary Theresa May signalled that the government had little appetite for imposing punitive measures on Russia, it says - "though she acknowledged that Litvinenko's murder amounted to a 'blatant and unacceptable' breach of international law".
The Times reports that the UK warned its allies to guard against further killings ordered by Russia.
"Despite the government's rhetoric, David Cameron was criticised for failing to impose robust sanctions," it continues.
"The Treasury imposed an asset freeze on two Russian henchmen, named by the inquiry as Litvinenko's assassins, but it was unclear whether they have any assets in the UK."
The home secretary said she would ask the director of public prosecutions to consider issuing fresh extradition requests for Mr Lugovoi and Mr Kovtun, the Times adds.
The Independent pictures a serious-looking Mr Putin chairing a meeting at the Kremlin on Thursday on its front page, and the paper conveys Moscow's anger at the inquiry.
"David Cameron said that the report had only confirmed what the government believed - but the prime minister stopped short of imposing immediate sanctions against Russia and Mr Putin, whose assistance is required in dealing with the crisis in Syria and tackling the threat from Isis," it says.
"Mr Litvinenko's family called for economic sanctions and a travel ban on the Russian leader, and senior political figures called for stronger action from Number 10."
The Independent's stablemate the i says Russia accused the UK of "blatant provocation", while the Metro reports that the Russian ambassador said it was "absolutely unacceptable" that the inquiry concluded the Kremlin was involved.
The Telegraph says Mr Cameron criticised Mr Putin for presiding over the "state-sponsored murder" of Mr Litvinenko.
Crime and punishment
Mrs Litvinenko writes in the Times: "My son Anatoly and I listened yesterday as more than nine years after the murder of my husband Alexander (Sasha) Litvinenko, Sir Robert Owen delivered his report into his death.
"It was an emotional day, as friends and supporters gathered with us to hear his words. We had high hopes that Sir Robert would deliver the truth and we were not disappointed."
The Times invokes the title of Russian author Fyodor Dostoyevsky's novel Crime and Punishment to head its leading article.
Russia has been held responsible for Mr Litvinenko's murder - and Britain must ensure Moscow pays the price by enshrining sanctions against named individuals in law, it argues.
The Telegraph takes a similarly tough line.
"For reasons of realpolitik - from Moscow's power play in the Middle East to Europe's dependency on Russian gas - the government is reluctant to fracture relations irrevocably," it says.
"Yet now that an official inquiry has reached a quasi-judicial finding of guilt against the Russian state, David Cameron must act decisively.
"Not only must he widen sanctions against named Russians but he should emulate Heath's example by expelling all the diplomats in London suspected of working for the FSB.
"Anything less will be seen as weak in Moscow."
For the Guardian, it is an assassination in London that must carry a price in Moscow.
The paper argues that the most efficient way to do this is by "Europeanising" the issue.
The Guardian says: "After all, the Litvinenko assassination concerns all European democracies, not just Britain.
"Russian political opponents don't just live in London, nor can the reach of Russian agents ordered to eliminate dissidents overseas be considered limited to British territory.
"On the basis of the report, European governments should work towards a common sanctions list, targeting, by name, the Russian officials linked to criminal activity and human rights abuses."
The Independent continues the theme by saying Russia cannot be allowed to get away with murder.
"A man has been murdered; his grieving widow has been on a long and almost unimaginably grim journey in the search for justice. This is the personal tragedy of the case, and it is awful," it says.
"The wider picture is of an already strained bilateral relationship that is now broken, and will take years to rebuild."
In other news, the Mirror leads with what appears to be another blow for the UK's struggling steel industry.
The paper says future Royal Navy warships could be built with foreign steel because it is cheaper than British steel.
The Mirror says: "Furious union leaders rounded on the government after defence minister Philip Dunne let slip steel for the fleet of Type 26 frigates could be supplied from abroad with multi-billion pound contracts - denying our own foundries the sort of vital cash that could secure their futures."
Responding to a Freedom of Information request, the Ministry of Defence told the Mirror: "As for all major defence equipment projects, it is the responsibility of our contractors... to buy the steel on the basis of cost, time and quality."
The Mirror comments that these are tough times for the British steel industry - which are being made even tougher by the government.
In the Express, there is relief for some of those affected by the recent serious flooding in Cumbria.
The paper says the county council has been given special dispensation by the government to re-house flood victims in homes that had been intended for 30 refugee families fleeing the civil war in Syria.
A county council spokesman tells the Express: "Before the floods Cumbria was among the first to offer assistance to Syrian refugees. To date, all the refugees that have come to the UK have been successfully allocated to other parts of the country.
"We will keep this situation under review but obviously our focus has to be on supporting our own communities through these difficult times."
The Express describes it as a "common sense" decision that will "mean so much to families who were struggling to find somewhere to stay while their own houses are made habitable again".
The Times reports that scientists have worked out that the human brain is big enough to store the contents of 4.7 billion books.
"Tolstoy's War and Peace. Russell Brand's My Booky Wook. David Evans's seminal text Does God Ever Speak Through Cats? The human brain has enough storage space to hold these and every book ever published 36 times over, a study has found," it says.
"Scientists claim that the part of the brain that deals with memory has a capacity 10 times bigger than previously thought.
"There may even be space for David Daggett's 1799 pamphlet Sun-beams May Be Extracted from Cucumbers, But the Process is Tedious."
Terry Sejnowski, professor of computational neurobiology at the Salk Institute in California, tells the Times that the findings came as a bombshell - although the practical implications were not yet clear.
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