A Novichok agent was used in Salisbury Description:BEN STANSALL/Getty

Several countries could have made the nerve agent used in the chemical attack on Russians Sergei and Yulia Skripal in Salisbury, UK, weapons experts have told New Scientist.

British Prime Minister Theresa May says that because it was Russia that developed Novichok agents, it is “highly likely” that Russia either attacked the Skripals itself, or lost control of its Novichok to someone else who did. But other countries legally created Novichok for testing purposes after its existence was revealed in 1992, and a production method has even been …