Leader comment: This is Russia's weak spot

In The Art of War, the famous Chinese strategist Sun Tzu wrote: 'So in war, the way is to avoid what is strong, and strike at what is weak.'

Russian President Vladimir Putin (Kremlin Pool Photo via AP)

Fortunately the UK is not at war with Russia, despite that country’s refusal to explain how one of its chemical weapons was used to attack several people on British soil. But that did not stop Kremlin spokeswoman Maria Zakharova from saying: “Who does Britain think it is, issuing ultimatums to a nuclear power?”

This rather gauche remark, which seemed to dismiss the UK’s nuclear weapons, was clearly designed to intimidate.

However, there is one area in which Britain is far stronger than Russia – freedom of speech. Harsh words may not seem like much of a response but they do have an impact.

The greater the level of fuss the UK can kick up about Moscow’s actions, the more people, companies and, possibly, countries will begin to turn away from Russia.

And, in our globalised world, that may end up being more of a sanction than the expulsion of 23 Russian diplomats announced yesterday by Theresa May.