To judge from the British government’s robust response to the chemical weapons attack on the English cathedral city of Salisbury this month, Russian President Vladimir Putin is up to his old tricks again. The Russian government, of course, forcibly rejects any suggestion that it was involved in the assassination of former Russian spy Sergei Skripal and his daughter Yulia, whom the British security forces believe were poisoned with the Russian-made nerve agent novichok, which chemical weapons experts say is only produced at Russia’s Shikhany military research centre.

Both Mr Skripal, a former Russian intelligence officer who spied for British intelligence and came to live in Britain as part of a spy swap, and his daughter are said to be in a critical condition as a result of being exposed to the nerve agent, as is a British policeman who went to investigate the initial poisoning incident. And, after conducting an exhaustive investigation into the causes of the poisoning, where experts from the British military’s Porton Down chemical weapons research laboratory have been involved, the British government clearly believes it has sufficient evidence to believe Russia was responsible for the attack. As a result, British Prime Minister Theresa May is now drawing up a wide-ranging raft of punitive measures against Moscow, starting with the expulsion of 23 Russian diplomats based in Britain, the largest such expulsion since the height of the Cold War in the 1980s. In addition, British officials are planning to tackle Russian money-laundering activities in Britain, while the government has announced no British officials or members of the royal family will be travelling to this year’s football World Cup, which is being held in Russia this summer.

Indeed, there were expectations among some British commentators that the measures would be even more severe after  May’s initial response to the nerve agent attack, when she gave the Russians an ultimatum to clarify whether they were involved. It was an ultimatum the Russians happily ignored. But  May was unable to go further because, as some of Britain’s European allies like France are now pointing out, you cannot accuse a country of wrong-doing unless you have incontrovertible proof to justify your case which, in the case of the Salisbury poisoning, the British authorities do not yet appear to have. Yes, all the circumstances suggest some form of Russian involvement, the fact, for example, the primary victim was a former Russian spy, and that the substance used in the assassination attempt was developed exclusively in Russia.  And, as in any good detective story, the Russians also have a compelling motive for wanting to silence their former military intelligence officer after it emerged Mr Skripal may have been working with former MI6 intelligence officer Christopher Steele, the man who wrote the damning document on US President Donald Trump’s ties with Russia that is now being scrutinised by American investigators. There are, then, already myriad competing conspiracy theories about who was responsible for the Salisbury attack, and why. Indeed, some supporters of British opposition leader Jeremy Corbyn are even suggesting it was carried out by Britain’s MI5 domestic security service to discredit Mr Putin. And this is precisely how Mr Putin, drawing on his previous experience as a master-spy in the former Soviet KGB intelligence agency, would like to have it.

Central to the success of any serious intelligence operation is the concept of deniability or having the ability to hurt or damage your enemies without them having sufficient evidence to accuse the perpetrators of involvement.

And, as someone who has closely followed Mr Putin’s transformation from putative liberal democrat to uncompromising autocrat over the past two decades, I can see all the hallmarks of a classic Putin operation in the way the Salisbury attack was carried out.

From Russia’s point of view, a traitor has been silenced and a clear message has been sent to other British-based Russian dissidents of the price they are likely to pay for crossing the Russian hardman. Indeed, following the Salisbury attack, the British authorities are now under pressure to review the investigations into a number of Russian dissidents who have recently died in suspicious circumstances in the UK, including the exiled tycoon Boris Berezovsky, who was found hanged in his Berkshire home in 2013.

At the same time, the assassination attempt has been carried out without the British authorities being able to find sufficient evidence to link the Russians directly to this audacious attack on British soil. In many respects an operation like this is very much in keeping with Russia’s alleged involvement in trying to interfere in America’s 2016 presidential election campaign.

There is plenty of circumstantial evidence that Russia tried to influence the election’s outcome in Mr Trump’s favour. But, despite the US political and security establishments initiating a number of inquiries, no conclusive evidence has yet been produced to prove it.

    The writer is a British journalist

    I would, moreover, like to add one other possible motive for Russian involvement in the Salisbury attack. Another of Mr Putin’s traits is an opportunistic desire to exploit a perceived weakness in his adversaries. His decision, for example, to launch Russia’s military intervention in Syria was taken in the belief that the Obama administration would not oppose it.

With Britain in the midst of negotiating its withdrawal from the EU, the Russians are keen to know what impact this is likely to have on future European cooperation, especially in the realms of defence and security.

And what better way to test the resolve of the Europeans to protect themselves than to disperse a deadly nerve agent in the heart of tranquil England?