Young’s trial commenced on 19 June 1972, at St Albans Crown Court. He was charged with two counts of murder, two counts of attempted murder, and two counts of administering poison. Young pleaded not guilty, and seemed confident that he would be acquitted, as his previous conviction could not be entered into evidence, and he felt it would be impossible to identify him as the only person with the means to poison Egle and Biggs.
He was delighted at the media hype that surrounded his trial, and did his best to appear sinister, in an attempt to unnerve the jury and assembled gallery, but was reportedly less than thrilled with the sobriquet ‘The Teacup Poisoner’, which he felt too parochial, belittling his skill and knowledge. He thought 'World Poisoner' more appropriate.
He hadn’t reckoned with the advances made in forensic science in the decade since the death of his stepmother, however, and the effect that the reading of tracts of his diary, in which he cold-bloodedly lists the effects of his poisons, would have on the jury: he was found guilty on all charges on 29 June 1972, receiving four life sentences.