Britain's diplomatic response to the possible poisoning of Sergei Skripal is limited by Brexit

Even the absence of Harry Kane from World Cup matches in Moscow or St Petersburg would be unlikely to change the course of Russian foreign policy

Boris Johnson says the Government will respond ‘robustly’ if it is shown that Russia was involved in Skripal's ailing health (Rex)

The case of Sergei Skripal and his daughter Yulia is, as almost everyone readily acknowledges, a highly suspicious affair. Those suspicions focus on whether they were victims of an officially sanctioned attack by the Russian authorities, motivated perhaps by Mr Skripal’s career as a double agent, a possible quest for revenge hardly ameliorated by a judicial pardon granted to him some years ago as part of an exchange of agents with the British.

While we must let investigations take their course, there are unavoidable echoes of the fate of Alexander Litvinenko in 2006, and the Foreign Secretary has said as much, adding, that Russia has become a “malign and disruptive force”.

Boris Johnson – under the usual caveats about the continuing police enquiries and, for a change, not shooting from the lip – told the Commons that “Her Majesty’s Government will respond appropriately and robustly”. The Government, he went on, will “take whatever measures we deem necessary to protect the lives of the people in this country, our values and our freedoms”. These may include the absence of British diplomats at the football World Cup in the summer, but will presumably stop short of the England team boycotting the event. There could be economic sanctions too, though the Foreign Office may be overestimating British financial clout these days.

Even the absence of Harry Kane from matches in Moscow or St Petersburg would be unlikely to change the course of Russian foreign policy. Vladimir Putin, after all, is the man who annexed Crimea under the noses of an astonished and anguished international community. Mr Putin it was who decided to call President Obama’s bluff about “red lines”, and got away with it. He has defied the United Nations, endured international sanctions, arguably interfered in a US presidential election and, if so, played Donald Trump like a fool for the past two years. We can be relatively confident Mr Johnson does not represent an intimidating figure to the Kremlin.

Even if Britain were not leaving the European Union, persuading the Russians to abide by the usual international courtesies and the domestic laws of other nations would be a challenge. It is at least conceivable that serious economic sanctions imposed by France, Germany, Britain and the other EU members – the largest economic bloc in the world – might cause the Russians to think twice about some marginal decision to liquidate a traitor or dissident. As thing stand now though, with Brexit fracturing longstanding friendships and alliances, Britain’s “robust” response doesn’t amount to very much. It is rather as if Andorra or San Marino were to try to threaten the UK. As so often in the past, the British independent nuclear deterrent is of no use in this dispute.

More than that, what this present episode reminds us is that Brexit will force the British Government to compromise and accommodate itself to all manner of questionable regimes around the world – including Russia – in the search for trading partnerships that will be desperately needed.

The problem with so many of the emerging nations that Liam Fox approaches is that they often share few of the values that the UK holds dear, and certainly not to the degree that most of our close neighbours do.

Still, at least it can be said that on this occasion – unlike after the poisoning of Alexander Litvinienko – the British authorities have been quick to react to the possibility of involvement by a foreign state on UK soil. If our diplomatic response may be compromised by the consequences of our decision to depart the EU, it is nonetheless vital that ministers take the proper action to ensure the safety of people living here.

The recent Winter Olympics may one day be remembered as the moment when peace broke out on the Korean Peninsula, but a post-Brexit Britain is going to have to find a more meaningful arena in which to play power games than the Luzhniki stadium in Moscow.