PRIME Minister Theresa May has said the government will make immediate moves to dismantle the Russian espionage network in the UK after they failed to explain the attack on Sergei and Yulia Skripal.

Speaking in the House of Commons yesterday, Mrs May said: “There is no other conclusion 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”.

On Monday, Mrs May said Novichok, a Russian military-grade agent, had been used to publish the former spy and his daughter in Salisbury on March 4.

Mrs May said the government “had been right” to offer Russia the opportunity for an explanation, but told the House that the state’s response used “sarcasm and defiance” and showed “complete disdain” in providing no explanation on how the chemical weapon had come to be used in the UK.

She said the incident was part of “a well established pattern of Russian state aggression” and must be met with “a full and robust response”.

The UK will now expel 23 Russian diplomats, in the largest single expulsion seen in this country for more than 30 years.

The prime minister also announced proposals for new powers to detain potential spies at the UK border, and said the actions taken would aim to damage the Russian espionage network “for years to come”.

Mrs May said it was essential that the UK now “comes together” with allies, and said she had support from the United States, France and Germany, and had received “strong expressions of support” from NATO and the EU.

The United Nations security council was also set to meet yesterday afternoon to discuss the response to the incident.

Mrs May said the UK’s relationship with Russia “cannot be the same”.

And she said: “This was not just an act of attempted murder in Salisbury, it is an affront to the prohibition on the use of chemical weapons.”

Leader of the opposition Jeremy Corbyn also condemned the “utterly reckless” and “abonimable” act.

said the nerve agent attack on Sergei and Yulia Skripal was “highly likely” to have been state-ordered by Russia.

Addressing MPs in the House of Commons on Monday, Mrs May said the substance used to poison the pair was “clearly a military grade nerve agent of the type developed by Russia”, before naming it as Novichok.

Mrs May said it was “highly likely that Russia was responsible” for the attack “based on the positive identification of this chemical agent by world-leading experts at the Defence Science and Technology Laboratory at Porton Down; our knowledge that Russia has previously produced this agent and would still be capable of doing so; Russia’s record of conducting state-sponsored assassinations; and our assessment that Russia views some defectors as legitimate targets for assassinations”.

Russia’s ambassador in London has been summoned to the Foreign Office to explain whether the attack was planned by the Russian state, and an update was expected from Mrs May yesterday afternoon after the Journal went to press.

She said: “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 it got into the hands of others.”

And she said the government “will not tolerate such a brazen attempt to murder innocent civilians on our soil”.

“This 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.”

Mrs May said if government does not receive “a satisfactory response” from the ambassador, “we will conclude that this action amounts to an unlawful use of force by the Russian state against the UK, and I will come back and set out the response”.

Foreign Secretary Boris Johnson summoned the Russian ambassador to the Foreign Office on Monday afternoon and asked him “to account for how this Russian-produced nerve agent could have been deployed in Salisbury against Mr Skripal and his daughter”.