Is spy 'poisoning' Russia vendetta or rogue mission?
If the former MI6 spy was poisoned, did agents take it upon themselves to settle a grudge or was the Kremlin involved in any way?
Tuesday 6 March 2018 20:53, UK
As Sergei Skripal and his daughter Yulia fight for their lives in a Salisbury hospital, the finger of blame in the Western press invariably points towards the Kremlin.
"It didn't take them long," said Kremlin spokesman Dmitri Peskov, adding that Mr Skripal's was a "tragic case" and that Moscow was ready to co-operate with the British authorities if only the British were to ask.
But as with so much in Russia, nothing is self-evident.
Why - eight years after Mr Skripal was pardoned by then president Dmitry Medvedev - should he become a target?
:: CCTV shows 'persons of interest' in spy investigation
Old grudges die hard in the world of espionage and of course President Putin, as a former KGB officer himself, knows that well.
But Mr Skripal had been working as a double agent back in the 1990s. These would have been very old grudges.
Andrei Soldatov, an author and expert on the Russian secret services, tweeted earlier: "If true, it's against all rules - Skripal didn't defect. He was swapped, and for that - pardoned."
If this is indeed a targeted assassination attempt, proving how far up the food chain it goes will be difficult.
:: LIVE: Kremlin denies 'poisoning' Russian MI6 spy
Obvious parallels are being drawn with the case of Alexander Litvinenko, who wrote a letter on his death bed in 2006 charging Vladimir Putin with his death.
"You may be able to shut one man up," he wrote. "The noise of protest all over the world will reverberate in your ears, Mr Putin, to the end of your life".
It was not for another 10 years that the UK's public inquiry into Mr Litvinenko's murder at least partially backed up that claim.
Sir Robert Owen concluded that it had been an FSB operation "probably approved" by the agency's then director Nikolai Patrushev and Mr Putin.
:: Who is Russian double agent Sergei Skripal?
"It is known that the Russian government pursues vendettas," says Nikita Petrov, a historian and specialist on the Soviet security services.
"Even if the Russian government is innocent in this situation, it can never be entirely free from suspicion."
The view in Russia is that this is a provocation by the West.
Andrei Lugovoi and Dmitri Kovtun, the two men suspected of poisoning Mr Litvinenko, have both been saying as much.
"The Britons suffer from phobias. If something happens to a Russian, they immediately start looking for a Russian trail," Mr Lugovoi told Russian news agency Interfax.
He is now a member of the Russian parliament and was awarded a state medal for "services to the fatherland" as the Litvinenko inquiry was taking place in London.
It is certainly not inconceivable that Russian intelligence operatives could be at work bumping off inconvenient personnel on the orders of the Kremlin.
Especially if they get the feeling they are not keeping quite the low profile they should.
"If Russians were behind it, it came out of Moscow," Russian security and politics expert Mark Galeotti told me.
"And therefore we can assume it was a state sanctioned hit."