Factbox - A few facts about the nerve agent Novichok

British Prime Minister Theresa May said on Monday it was "highly likely" that Moscow was responsible for the poisoning in the English city of Salisbury of a Russian former double agent with Novichok, one of the deadliest chemical weapons ever developed.* First developed in the former Soviet Union in the 1970s and 1980s, Novichok, or "newcomer", is a series of highly toxic nerve agents with a slightly different chemical composition than the more commonly known VX and sarin poison gases.* Novichok