A former police volunteer claims to have discovered the identity of the figure behind some of the most shocking crimes in British history, unmasking the 19th-century murderer who terrorised the nation as Jack the Ripper.

Sarah Bax Horton – whose great-great-grandfather was a policeman at the heart of the Ripper investigation – has unearthed compelling evidence that matches witness descriptions of the man seen with female victims shortly before they were stabbed to death in 1888 in the East End of London.

Her detective work has led her to Hyam Hyams, who lived in an area at the centre of the murders and who, as a cigar-maker, knew how to use a knife. He was an epileptic and an alcoholic who was in and out of mental asylums, his condition worsening after he was injured in an accident and unable to work. He repeatedly assaulted his wife, paranoid that she was cheating on him, and was eventually arrested after he attacked her and his mother with “a chopper”.

Significantly, Ms Bax Horton gained access to his medical records and discovered dramatic details. She told The Telegraph: “For the first time in history, Jack the Ripper can be identified as Hyam Hyams using distinctive physical characteristics.”