National Security and Russia

After Georgia, Crimea, Ukraine, Alexander Litvinenko and now Salisbury, I believe that we are entering, if not a period of cold war, at least a period of cool war in our relations with Russia, which is likely to last for some time. In that context, does the Prime Minister agree that the robust decision of 18 of our allies to expel Russian diplomats is likely to give Russia pause for thought and hurt it far more than our unilateral expulsions in 1971?