Quantity of nerve agent dose thought to have been used suggests it was created as a weapon

The former Russian spy Sergei Skripal and his daughter Yulia were poisoned with a dose of liquid nerve agent as large as 50-100 grams, the director general of the international chemical weapons watchdog has told the New York Times. [Soon after publication of the interview with its head, the Organisation for the Prohibition of Chemical Weapons withdrew this claim saying it could make no such estimate. See footnote below.]

Ahmet Üzümcü, of the Organisation for the Prohibition of Chemical Weapons, said the amount of novichok – a military-grade nerve agent developed by the Soviet Union – used was significantly more than needed for research purposes, which indicates it was likely created for use as a weapon.

In an interview with the New York Times, Üzümcü said he had been told that about 50-100g of the nerve agent was thought to have been used in the attack in Salisbury – 100g is equivalent to 100ml, the maximum amount of liquid allowed in carry-on luggage on a flight.

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He said: “For research activities or protection you would need, for instance, five to 10 grams or so, but even in Salisbury it looks like they may have used more than that, without knowing the exact quantity, I am told it may be 50, 100 grams or so, which goes beyond research activities for protection.”

Samples of the agent were collected from the door handle of the Skripal home, the park bench where the two collapsed and “a few other places where the Skripals were present,” he added.



“One thing, perhaps, which is important to note is that the nerve agent seems to be very persistent,” Üzümcü said. “It’s not affected by weather conditions. That explains, actually, that they were able to identify it after a considerable time lapse. We understand it was also of high purity.”

Last month, the Department for Environment, Food and Rural Affairs confirmed the nerve agent used in the attack was delivered in liquid form. Police had previously said they believed the pair had been poisoned at the front door of Skripal’s home as specialists found the highest concentration of the nerve agent on the door.

Almost 200 military personnel in protective suits and boots will spend months decontaminating nine sites in the town.

• This article was amended on 4 May 2018 to make prominent note of the fact that the OPCW had withdrawn Ahmet Üzümcü’s assertion about the quantity of novichok used in the Skripal poisoning. On 4 May 2018 at 17:20 the Guardian reported the OPCW’s disavowal.