More than 130 people could have been exposed to the deadly nerve agent novichok during the Russian spy attack in Salisbury, Theresa May said on Monday.
The prime minister told MPs that hundreds of British citizens had been put in danger by the “utterly barbaric” act which left Sergei Skripal, a former Russian intelligence official, and his daughter Yulia in a coma.
May said that no country other than Russia had the combination of “the capability, the intent and the motive” to carry out such an attack.
“Sergei and Yulia Skripal remain critically ill in hospital. Sadly, late last week, doctors indicated that their condition is unlikely to change in the near future, and they may never recover fully,” she said.
“This shows the utterly barbaric nature of this act, and the dangers that hundreds of innocent citizens in Salisbury could have faced.”
She added: “We assess that more than 130 people in Salisbury could have been potentially exposed to this nerve agent.”
May pledged the UK, together with its EU and Nato allies, would “face down” the Russian threat and defend its infrastructure, institutions and values. “We will act to protect our national security and to keep our people safe.”
More than 50 people have been assessed in hospital, including DS Nick Bailey, who was discharged last week saying his life would probably never be the same after being exposed.
Inspectors from the Organisation for the Prohibition of Chemical Weapons (OPCW) have begun working at the scene of the attack on the Skripals, with officials saying it would take two to three weeks to complete laboratory analysis of samples.
Local reports suggested that buildings in public areas in Salisbury would be decontaminated later this week, with the operation expected to include the Zizzi restaurant and the Mill pub, which were visited by the pair.
In her Commons statement on UK national security and Russia, May said the government had evidence that Russia, which claimed it had destroyed its chemical weapons stockpile, had explored ways of exporting them.
“We have information indicating that within the last decade, Russia has investigated ways of delivering nerve agents, probably for assassination, and as part of this programme has produced and stockpiled small quantities of novichok. Clearly, that is in contravention of the chemical weapons convention.”
The prime minister also said that since the attack Russia had advanced 21 different arguments to try to distance itself from the attacks.
“They provided no explanation as to why Russia has an undeclared chemical weapons programme, in contravention of international law. No explanation that they could have lost control of their nerve agent, and no explanation as to how this agent came to be used in the United Kingdom,” she said.
What is novichok?
Novichok refers to a group of nerve agents that were developed by the Soviet Union in the 1970s and 1980s to elude international restrictions on chemical weapons. Like other nerve agents, they are organophosphate compounds, but the chemicals used to make them, and their final structures are considered classified in the UK, the US and other countries. By making the agents in secret, from unfamiliar chemicals, the Soviet Union aimed to manufacture the substances without being impeded.
“Much less is known about the novichoks than the other nerve agents,” said Alastair Hay, an environmental toxicologist at the University of Leeds who investigated the use of chemical weapons against Iraqi Kurds in Halabja in 1988. “They are not widely used at all.”
The most potent of the novichok substances are considered to be more lethal than VX, the most deadly of the familiar nerve agents, which include sarin, tabun and soman.
And while the novichok agents work in a similar way, by massively over-stimulating muscles and glands, one chemical weapons expert told the Guardian that the agents do not degrade fast in the environment and have “an additional toxicity”. “That extra toxicity is not well understood, so I understand why people were asked to wash their clothes, even if it was present only in traces,” he said. Treatment for novichok exposure would be the same as for other nerve agents, namely with atropine, diazepam and potentially drugs called oximes.
The chemical structures of novichok agents were made public in 2008 by Vil Mirzayanov, a former Russian scientist living in the US, but the structures have never been publicly confirmed. It is thought that they can be made in different forms, including a dust aerosol that would be easy to disperse.
The novichoks are known as binary agents because they become lethal only after mixing two otherwise harmless components. According to Mirzayanov, they are 10 to 100 times more toxic than the conventional nerve agents.
The fact that so little is known about them may explain why Porton Down scientists took several days to identify the compound used in the attack against Sergei and Yulia Skripal. While laboratories around the world that are used to police chemical weapons incidents have databases of nerve agents, few outside Russia are believed to have full details of the novichok compounds and the chemicals needed to make them.
“Instead, they have treated the use of a military-grade nerve agent in Europe with sarcasm, contempt and defiance.”
The Labour leader, Jeremy Corbyn, initially appeared to be toughening his position on Russia’s culpability for the attack, saying the country had “offered nothing in response except for denials and diversion”.
He then repeated his view that Russia was directly “or indirectly’ responsible for the Salisbury attack – again raising the possibility that the Putin regime could have lost control of the deadly nerve agent.
His comments prompted a barracking from the Tory benches, with the former minister Mark Francois scolded by the Speaker for whistling the Russian national anthem, while Labour MP John Woodcock challenged his leader’s claims that he had been “a robust critic” of the actions of the Russian government for more than 20 years.
It came after the United States, EU, Canada and Ukraine ordered the expulsion of dozens of Russian diplomats in response to the attack, in a dramatic show of solidarity which delivers a blow to Vladimir Putin’s intelligence networks.
“If the Kremlin’s goal is to divide and intimidate the western alliance, then their efforts have spectacularly backfired,” May said.