The UK will expel 23 Russian diplomats over the poisoning of former double agent Sergei Skripal and his daughter Yulia in the single biggest expulsion in more than 30 years.
Theresa May said on Tuesday that a deadline issued on Monday for Moscow to provide an explanation for how a Russia-made nerve agent had ended up in Salisbury met “complete disdain”.
“They have treated the use of a military grade nerve agent in Europe with sarcasm, contempt and defiance,” 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.”
Skripal, 66, and his daughter Yulia, 33, were found unconscious on a bench outside a shopping centre in the southern English city of Salisbury on March 4, after they were poisoned with a nerve agent.
A former double agent, Skripal betrayed dozens of Russian agents to British intelligence before his arrest in Moscow in 2004.
Speaking in parliament, May announced a range of responses to the alleged murder attempt, including withdrawal of an invitation to Sergei Lavrov, Russian foreign minister, to visit the UK.
Cabinet ministers and members of the royal family would not attend the World Cup in Russia this summer.
May said the expelled diplomats were identified as “undeclared intelligence officers” and were given one week to leave the country.
Proposals for new legislation to “harden our defences” against “all forms of hostile state activity” would be developed urgently, May said.
She also announced plans to increase checks on private flights, customs and freight, and freeze Russian state assets where there is evidence they may be used to threaten the life or property of UK nationals or residents.
The Russian embassy in London called the expulsion of diplomats a “hostile action” which is “totally unacceptable, unjustified and shortsighted”.
In a statement, the embassy said Alexander Yakovenko, Russia’s ambassador, had been summoned to the UK’s foreign office on Tuesday where he was informed of the punitive measures.
“All the responsibility for the deterioration of the Russia-UK relationship lies with the current political leadership of Britain,” the statement said.
On Monday, May told the UK parliament it is “highly likely” that Russia is responsible for the “reckless and despicable act”.
She said Skripal and his daughter were poisoned with a military-grade nerve agent of a type developed by Russia, which is part of a group of nerve agents known as Novichok.
“Either this was a direct act by the Russian state against our country, or the Russian government lost control of its potentially catastrophically damaging nerve agent and allowed it to get into the hands of others.”
May issued a deadline for Russia to provide an explanation by the end of Tuesday.
The poisoning of Skripal and his daughter has drawn comparisons to the murder of Alexander Litvinenko in 2006. The former Russian spy died three weeks after drinking green tea laced with radioactive polonium-210 at London’s Millennium Hotel.
Russia denied involvement in his death.
A British inquiry into the 43-year-old’s death said Moscow had “probably” ordered the poisoning of Litvinenko, who lived in exile in Britain.