In boyhood Graham Young developed an unhealthy interest in toxicology and Nazism – and friends and family paid the price. Broadmoor failed to rehabilitate him and the workplace provided the opportunity for further poisonings…

By the age of 14, Young was also making explosives in his garden shed, and still doodling the swastika and skull and crossbones on bits of paper. There were other tell-tale signs. He had a cruel sense of humour, delighting in causing embarrassment or accidents.

And he had at last found another hero to stand alongside Adolf Hitler. It was a not a political figure, nor even a military one, but the Victorian poisoner William Palmer, who had claimed some 14 victims.

The teens are an awkward period for many youngsters, spawning moodiness and pimples. But Graham Young did not develop pimples. In 1961 he marked his adolescence by systematically poisoning his family…