Putin has scored a spectacular own goal and is now more isolated than at any time since he came to power

The Russians no doubt believed they could get away with the assassination attempt of a spy and his daughter. That was a grave miscalculation, writes Con Coughlin

The Ministry of Foreign Affairs in Moscow, Russia. Dozens of countries have expelled Russian diplomats after the use of a nerve agent to poison a former Russian spy and his daughter / EPA

It is a measure of the growing international isolation that Russia is suffering as a result of the Salisbury poisoning that countries as far apart as Moldova, Australia and Ireland have now agreed to join the diplomatic offensive against Moscow.

The Kremlin clearly had no expectation that by allowing a Russian-made military grade nerve agent to be used in the attempted assassination of former military officer Sergei Skripal and his daughter Yulia on British soil, it would provoke such a furious response from the international community.

The Russians, of course, deny any involvement in the Salisbury poisoning and have sought to lay the blame elsewhere, including the ludicrous proposition that it was carried out by British agents using nerve gas made by the Porton Down chemical weapons research establishment in Dorset as part of a dastardly plot to discredit Moscow.

This kind of nonsense is very much in keeping with the Russians’ modus operandi under President Vladimir Putin, who himself served as a senior KGB officer before choosing a career in politics.

At the heart of any Russian intelligence operation lies the concept of deniability – making sure there is no evidence to link an operation back to Mother Russia. This might explain why the British authorities currently have an estimated 14 cases relating to the unsolved deaths of Russian dissidents who have recently died in mysterious circumstances.

The Russians no doubt believed they could employ the same tactic in the assassination attempt on Mr Skripal as he enjoyed a casual Sunday lunch in the heart of rural England.

But they gravely miscalculated the ability of Britain’s intelligence services to discover the nature of the nerve agent used in the assassination attempt (Mr Skripal and his daughter have been in a coma ever since and are said to be highly unlikely to recover).

And they totally misjudged the resolve of British Prime Minister Theresa May, not only to hold the Russians accountable but to organise a global diplomatic boycott of the Kremlin.

Consequently Mr Putin now finds himself more isolated than at any time since he came to power, an embarrassing predicament for someone who sees himself on a par with the American and Chinese leaders. And it also leaves him with little room for manoeuvre.

To date, more than two dozen countries and international organisations such as Nato have joined the global international boycott of Moscow in support of Britain, with more than 100 Russian diplomats sent home.

Many of these so-called diplomats are nothing of the sort but have been working as covert operatives on behalf of Russia’s FSB intelligence service and have been spying on the host nations that granted them diplomatic status. Thus, by orchestrating the diplomatic expulsions, Mrs May has also overseen the most damaging assault on Russia’s overseas intelligence-gathering operation since the end of the Cold War.

Indeed, the reason Mrs May has been able to orchestrate such an impressive global response in support of Britain’s position is the quality of the intelligence Britain has been able to provide about Russia’s involvement in the attack, including the precise location of where the nerve agent originated. The Russians may continue to deny their involvement but no one is listening.

Mr Putin, by contrast, finds himself very limited in the options he can take by way of retaliation.

He would, of course, like to orchestrate his own global diplomatic offensive against all those countries who have provided moral support to the British position.

But who, in reality, can Mr Putin call on to back Russia’s position? Iran, Syria, North Korea? Qatar? None of these countries have the kind of diplomatic clout to match the impressive array of countries that have backed Britain.

And Mr Putin needs to tread very carefully when it comes to using any of the more clandestine tools in the Russian arsenal, such as cyber-attacks and disseminating fake news, to retaliate against Britain and its allies.

Another problem Mr Putin faces is that, while in the past many of his transgressions have been overlooked by the international community, now politicians are far more aware of Russian attempts to interfere in their domestic affairs, not least because of Moscow’s well-documented attempts to meddle in the 2016 US presidential election.

Consequently foreign governments are only too aware of the activities of Mr Putin’s troll factory in St Petersburg and the fake news pumped out on state-owned Russian televisions stations such as RT.

The other consideration Mr Putin needs to take into account as he weighs his response is that he must not do anything to jeopardise the football World Cup due to take place in Russia in three months’ time.

The notion of organising an international boycott of the games has already been raised in Britain and it is not beyond the realms of possibility that it might become a reality if Russia were found to be involved in another gross breach of international protocols, such as initiating military action against one of the Baltic states.

The truth, though, is that Mr Putin's options are very limited when it comes to replying to the anti-Russia diplomatic offensive. He can, it is true, retaliate by expelling the diplomats of those countries who have come to Britain's aid in a classic tit-for-tat diplomatic response.

But by contrast to the international isolation Russia is now suffering, such measures are modest by comparison. For the only conclusion to be reached from Russia’s involvement in the Salisbury poisoning is that Mr Putin has scored a spectacular own goal, one from which it will take him many years to recover.

Con Coughlin is the Daily Telegraph’s defence and foreign affairs editor