Britain is expelling 23 Russian diplomats in response to the nerve agent attack on ex-spy Sergei Skripal in Salisbury.

And the UK has cut off all high-level contacts with Russia, including a boycott of this summer’s World Cup by Government ministers and members of the Royal Family.

Prime Minister Theresa May told MPs the individuals being kicked out in the biggest expulsion of its kind for more than 30 years had all been identified as undeclared spies. They have been given a week to leave.

Mrs May said Russia had failed to provide a “credible” explanation for how the Novichok nerve agent which it had developed came to be used in the attack on Mr Skripal and his daughter Yulia on March 4.

Theresa May made a statement to the House of Commons (

She said: “There is no alternative conclusion other than that the Russian state was culpable for the attempted murder of Mr Skripal and his daughter – and for threatening the lives of other British citizens in Salisbury, including Detective Sergeant Nick Bailey.

“This represents an unlawful use of force by the Russian state against the United Kingdom.”

The Russian embassy in London responded to the expulsions by saying they were “unacceptable, unjustified and shortsighted”.

Ambassador Alexander Yakovenko, who had been summoned to the Foreign Office ahead of Mrs May’s statement, said the UK Government’s actions were “absolutely unacceptable and … a provocation.”