Toxic is the first comprehensive history of nerve agents, tracing the spread of these terrible weapons from their Nazi origins to Russia's 2018 deployment of Novichok in Britain.

The deadliest means of chemical warfare yet developed, the first military-grade nerve agents were synthesised in Nazi Germany, with a massive industrial enterprise built for their manufacture - yet, strangely, the Third Reich never used them.

At the end of the Second World War, the victorious Allies were stunned to discover just how advanced and extensive the programme was. Exploiting the Nazis' knowledge, the Soviet Union and Western powers embarked on a new arms race: to develop their own nerve agents and munitions, amassing huge chemical arsenals.

Gradually, nerve agents spread elsewhere, first deployed in the Iran-Iraq War and then by terrorists in Japan. Despite arms control efforts and disposal of national stockpiles, they have been used again, in the Syrian Civil War and by assassins in Malaysia and Salisbury.

Yet - as the powers developing them have learnt - building, testing and disposing of nerve agents is itself an extremely difficult undertaking, with bitter consequences. Toxic recounts the grisly history of these weapons of mass destruction: a deadly suite of invisible, odourless killers.