THERESA May yesterday gave Russia’s Vladimir Putin until midnight tonight to explain the Salisbury spy poisoning — or face the wrath of Britain.

She told MPs it was “highly likely” ex-MI6 double agent Sergei Skripal and his daughter Yulia were attacked with a Russian-produced nerve agent called Novichok.

9 Theresa May said today that Russia was behind the poisoning attack on Sergei Skripal Credit: PA:Press Association

The PM revealed the chemical weapon used was designed by Russian scientists in the 1980s to kill thousands on the battlefield.

Stunned MPs shouted “shame” in the Commons as she said its “indiscriminate” use in targeting former Russian spy Sergei Skripal and his daughter Yulia “put the lives of innocent civilians at risk”.

Her comments come as the White House, and US Secretary of State Rex Tillerson described the scandal as an "outrage" and vowed to stick by Britain.

Mrs May spoke out as investigators probing the attack in Salisbury, Wilts, descended on a village six miles away. Some arrived in protective suits and put a street in lockdown.

What we know so far:

9 Russian spy Sergei Skripal and his daughter Yulia are fighting for their lives in hospital following nerve agent attack in Salisbury

9 Army chemical weapons experts and the police swarmed on sleepy Winterslow today Credit: PA:Press Association

9 Police and at least one ambulance were seen in a residential street in the village

9 Mrs May said the 'Kremlin is intent on dismantling the rules based world order' Credit: AFP or licensors

The PM concluded there were only “two plausible explanations” for what happened on March 4.

She said: “Either 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.”

Novichok agents are among the most deadly chemical weapons, and were designed to even permeate Nato chemical protection suits.

Reading out her devastating indictment, Mrs May listed further evidence amassed by spy chiefs pointing at Russia being to blame:

ITS record of conducting “state-sponsored assassinations”;

HOW it sees defectors as “legitimate targets” to be murdered, and;

INSISTING on still retaining the capacity to produce more of the devastating Novichok agents.

5 WAYS TO HIT BACK 1 — Kick out Russian diplomats: David Cameron did this after Alexander Litvinenko was poisoned in 2006. But the Kremlin would ­probably retaliate.

2 — Strip Russian media of its right to broadcast in the UK: PM could ask Ofcom to declare channels such as RT — formerly Russia Today — not fit to hold a licence.

3 — Stay away from World Cup in Russia: EU sport officials could be urged to boycott event, but this would not involve footballers.

4 — Toughen up sanctions: The Government could amend the ­sanctions and anti-money laundering bill to impose firmer rulings against human rights abusers.

5 — Freeze assets of Russian oligarchs: But this might hit as many Putin opponents as allies.

Russian President Vladimir Putin refuses to talk about the poisoning of Sergei Skripal until the UK gets 'to bottom of things'

9 Last week's attack has similarities with the killing of ex-Russian spy Alexander Litvinenko, who poisoned with Polonium-210 Credit: Getty - Contributor

What is Novichok and was the nerve agent used to poison ex-Russian spy Sergei Skripal? Novichok - the Russian for newcomer or newbie - is the name for a series of nerve agents developed by the Soviet Union in the 1970s and 80s. They are said to be the deadliest nerve agents ever created and reported to be five times more potent than the notorious VX gas. It is made of two relatively harmless materials which become fatal when mixed together, making it easier to transport under the radar. "It is designed to be undetectable for any standard chemical security testing, " Colonel Hamish de Bretton-Gordon told the Express. Novichok agents, dispersed as an ultra-fine powder rather than vapour, belong to the class of inhibitors called "organophosphate acetylcholinesterase". They prevent the normal breakdown of a neurotransmitter acetylcholine which, when it builds up, causes muscles to contract involuntarily. Because the victim's heart and diaphragm aren't functioning properly, this leads to respiratory and cardiac arrest. Those affected usually die from total heart failure or suffocation as copious fluid secretions fill their lungs. But even if they don't die from the nerve agent, the substance can also cause permanent nerve damage, leaving victims permanently disabled, Russian scientists have said.

9

Mrs May also insisted that Moscow must “immediately provide full and complete disclosure” of its Novichok nerve gas programme to the Organisation for the Prohibition of Chemical Weapons.

If Putin’s ambassador fails to explain what happened to its lethal nerve agent stock before midnight tonight, Mrs May said she will declare it “an unlawful use of force” by Russia against the UK. Holding out little hope that Moscow will come up with a “credible” explanation, the PM told the Commons: “We have led the way in securing tough sanctions against the Russian economy. “We must stand ready to take much more extensive measures. She added: “There can be no question of business as usual with Russia”. It emerged that earlier, Boris Johnson refused to shake hands with Russia’s Ambassador to London Alexander Yakovenko when he summoned him to the Foreign Office at 3.45pm. Mr Johnson issued the ultimatum instruction and told him of the British public’s outrage. The PM’s declaration — which senior Labour MP Yvette Cooper dubbed as “bold” — plunges Britain into the biggest crisis with Moscow since the end of the Cold War 28 years ago.

Zizzi in Salisbury closed after traces of nerve agent thought to have poisoned Sergei Skripal are found in the restaurant

9 An officer passes a barrier erected by police outside the Zizzi restaurant in Salisbury near to where former Russian double agent Sergei Skripal was found critically ill by exposure to a nerve agent Credit: PA:Press Association

9 Yulia Skripal and her dad, ex-Russian spy Sergei Skripal, 66, were found slumped unconscious on a bench in Salisbury on Sunday Credit: AP:Associated Press

Poisons linked to Russia in the past THERE are three known types of substance that have been linked to use to by Moscow, Bob Seely has said. Powerful opiods such as fentanyl - thought to have been used to overcome terrorists holding 900 people hostage in Moscow in 2002. Around 130 died. Radioactive toxins such as polonium-210 - like which killed Russian spy Alexander Litvinenko in 2006. It's lethal to humans if it is ingested. It causes acute liver and kidney damage and other symptoms similar to the final stages of cancer. It is hugely expensive to manufacture and is so toxic that its use is restricted Dioxins - used in the attempted assasination of former Ukrainian President Viktor Yushchenko in 2004

No10 refused to give further detail of what Mrs May’s threats would entail. She will report back to the Commons tomorrow afternoon.

The Sun revealed last week how the PM ordered Cabinet ministers to draw up “a full spectrum response” to punish Russia if proof emerged that it is the culprit.

Options include expelling Moscow’s diplomats from London, asset freezes and travel bans for Kremlin-linked oligarchs, as well as reinforcing Britain’s troops and jets on Europe’s eastern flank.

The PM and other Cabinet ministers last night began phoning world leaders to build as broad a consensus at possible to condemn Vladimir Putin’s regime - starting with French President Emmanuel Macron.

In a major early breakthrough US Secretary of State Rex Tillerson promised his support. He agreed the attack “clearly came from ­Russia” and said it would “certainly trigger a response”.

The EU and Nato also pledged support.

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The Russian Embassy kept silent on the PM’s demand. But a Russian foreign ministry spokeswoman in Moscow called the Commons statement “a circus show”.

Double agent Mr Skripal, 66, and Yulia, 33, remained critically ill.

Cops and Army teams yesterday entered Winterslow, Wilts, where investigators in protective suits loaded a white van on to a truck.

It is thought the van may have been used to remove Mr Skripal’s BMW from Salisbury.

Senior Tory Tom Tugendhat last night warned that England football fans in Russia for the World Cup could face revenge attacks for any sanctions from Kremlin thugs.

Former KGB officer claims he was warned he was being targeted by Russians alongside double agent Sergei Skripal