Spy poisoning reaction: Russia refuses to back down as it expels diplomats in tit-for-tat row

"They have blamed the UK, Ukraine, the Czechs, Kremlin critic Bill Browder, the Portland Down weapons research facility and poisoned pizzas," said Ian Bond, director of foreign policy at the Centre for European Reform and a former British diplomat in Moscow. "They have not suggested they lost control of the stuff, and I find that significant in itself."

So far, the British response has been a “model exercise” in coalition building, said Mr Bond: “The Kremlin will not have anticipated the participation of traditionally reluctant allies such as Italy."