Theresa May says it is 'highly likely' Russia responsible for spy poisoning
Theresa May has said it is "highly likely" that Russia was behind the nerve agent attack that landed an ex-spy, his daughter and a police officer in hospital.
The Prime Minister said the "military-grade" substance was of a type which has been developed by Moscow.
Former double agent Sergei Skripal and his daughter, Yulia, were found unconscious on a shopping centre bench in Salisbury, Wiltshire, on 4 March after apparently being poisoned.
They remain in hospital along with Detective Sergeant Nick Bailey, the first police officer to attend the scene.
In a statement to the Commons, Mrs May said experts at the Defence Science and Technology Laboratory at Porton Down had identified the substance responsible as being part of a group of nerve agents known as Novichok.
She said that given "Russia’s record of conducting state-sponsored assassinations; and our assessment that Russia views some defectors as legitimate targets for assassinations; the Government has concluded that it is highly likely that Russia was responsible for the act against Sergei and Yulia Skripal".
Mrs May said the only possible explanations were that "this was a direct act by the Russian state against our country, or the Russian government lost control of this potentially catastrophically damaging nerve agent and allowed it to get into the hands of others".
Russia's ambassador to the UK has been summoned to the Foreign Office to explain what has happened, the Prime Minister told the House of Commons.
But she added: "On Wednesday we will consider in detail the response from the Russian state. Should there be no credible response, we will conclude that this action amounts to an unlawful use of force by the Russian state against the United Kingdom, and I will come back to this House and set out the full range of measures that we will take in response.
"This attempted murder using a weapons-grade nerve agent in a British town was not just a crime against the Skripals. It was an indiscriminate and reckless act against the United Kingdom, putting the lives of innocent civilians at risk. And we will not tolerate such a brazen attempt to murder innocent civilians on our soil."
Labour leader Jeremy Corbyn called for "robust dialogue" with the Kremlin as a way of dialling down tensions between Russian and the UK.
He added: "The actions the Government takes once the facts are clear need to be both decisive and proportionate, and focused on reducing conflicts and tensions rather than increasing them."
To cries of "shame" and "disgrace" from Conservative MPs, Mr Corbyn also used the opportunity to attack the Tories for accepting money from Russian donors.
Former Conservative leader Iain Duncan Smith said Mr Corbyn should have risen "above party politics" in his response, while fellow Tory MP Johnny Mercer described the Labour chief's contribution as "one of the most shameful moments I've seen in my time in the House of Commons".
By contrast, SNP leader Ian Blackford said the Prime Minister must tell the Kremlin "we will not accept Russian interference in our democracy or in our way of life".
He added: "This kind of international outrage must never again be seen on our streets."