By Con Coughlin of the Daily Telegraph
Tyrants like Vladimir Putin are rarely in the habit of expressing remorse for their actions.
About the only time Putin has publicly hinted at feelings of regret was when he famously remarked that he regarded the collapse of the Soviet Union as "the greatest geopolitical catastrophe" of the 20th century.
We should hardly be surprised that Putin should pine for the good old days of Moscow's communist hegemony given that, following his successful re-election to serve another term as president, he is now set to rule almost as long as that other infamous Kremlin strongman, Josef Stalin.
Normally, though, Putin is not the kind of personality to reflect too deeply on his misjudgments.
On the contrary, he tends to portray his more outrageous acts, such as the invasion and illegal annexation of Crimea, or Russia's military intervention in Syria, as unqualified triumphs, even when the evidence suggests otherwise.
Moscow might now count Crimea — and the vital naval base at Sevastopol — as an integral part of the motherland, but the Kremlin has paid a heavy price for its flagrant breach of international law in the form of punitive sanctions.
Similarly, Putin's Syrian venture has turned out to be a poisoned chalice. By saving the Assad regime, his main achievement has been to ensure the survival of the world's most reviled dictator.
Now the same pattern of behaviour is evident in the Russian president's response to the international condemnation directed towards Moscow over the Salisbury poisoning.
Rather than indicating any sign of remorse that Russia has been blamed for the first chemical weapons attack on European soil since the end of the Second World War, he is simply trying to dismiss the incident as a stunt dreamt up by the West to discredit his beloved Russia.
This is a dangerous ploy by the Russian leader, as the overwhelming consensus in the West — with the notable exception of the more unreconstructed members of Jeremy Corbyn's cheerleading gang — is that the Kremlin was, directly or indirectly, responsible for the assassination attempt on Sergei Skripal and his daughter Yulia using the Russian-made nerve agent Novichok.
The attack, moreover, was very much in keeping with Putin's opportunistic modus operandi, where he scours the globe looking for his enemies' weaknesses and, once identified, seeks to exploit them for his own ends.
Thus, with Britain and the EU embroiled in difficult negotiations over the future of our relationship, Putin no doubt calculated that this might be an opportune moment to test the resilience of European cooperation on defence and security issues.
There is nothing Russia would like more than a weakened Britain and Europe, which is no doubt why the Russian-backed RT television station pays a handsome fee to Alex Salmond, a man who, at the very least, wants to destroy the United Kingdom.
Putin may well fool himself that he has succeeded in his goal of creating European discord after the craven message he received from EU president Jean-Claude Juncker congratulating him on his election "victory".
He can also point to the somewhat tepid EU declaration of support for Britain, which diplomats say was not as robust as it might have been because of the reservations of EU member states such as Greece, Italy and Hungary, which rely on Moscow for their economic survival.
The reality, though, is that, rather than creating divisions, the Salisbury poisoning has had a galvanising effect on the major Western powers, prompting a rare display of unity on the part of the US, France, Germany and Britain in condemning the attack.
In the UK, moreover, the assassination attempt, which also caused serious injury to a police officer attending the crime scene, has had the welcome effect of removing any remaining equivocation on the part of the vast majority of politicians on both the Right and Left about how to handle Putin's Russia.
Previously British foreign secretaries, from David Miliband onwards, have been reluctant to take an uncompromising line with Moscow in the belief that the best way to persuade Putin to mend his ways was through maintaining a constructive dialogue with the Kremlin. They were also mindful of the vast amount of Russian oil-wealth that flows through City institutions, both legally and otherwise.
The Salisbury attack has radically changed attitudes, to the extent that the British Government and its allies now seem determined to hold Putin to account. Among the many plans now under consideration by the national security council are measures to prevent Putin's allies from enjoying the easy access to the City that they enjoyed in the past.
I doubt this was the outcome Putin expected when the decision was taken to poison a Russian spy in England. And let's hope that, this time, the West's uncompromising response will make him rue Russia's involvement.