Mary Ann Cotton’s efforts have since been surpassed by Dr. Harold Shipman, but in her day she was reputed to be Britain’s most prolific serial killer.

Her trouble with the law began on JULY 12th, 1872, with the death of her stepson. His 10-year-old brother had died three months earlier, during a three-week period in which the mortality rate at Mary Ann Cotton’s home was alarming: her own baby and her live-in lover Joseph Natrass had also died suddenly.

When her second stepson died at her home in West Auckland, County Durham, her doctor refused to issue a death certificate. An autopsy revealed arsenic in the child’s stomach, and the poison was also found to have been responsible for two of the other deaths in Mary Ann Cotton’s home.

At her trial at Durham Assizes for her stepson’s murder, her defence claimed the child had been poisoned by arsenic flaking from green wallpaper. But the 40-year-old former nurse admitted buying arsenic, and the jury did not believe her story that she purchased it to kill bedbugs.

Convicted and sentenced to death, Mary Ann Cotton was suspected of at least 13 more murders, but she attracted public sympathy when a baby born to her in Durham Prison was taken from her five days before her execution. The father was another lover, the local excise officer.

She’d had three husbands, the last one bigamous, and her murders were believed to have been motivated by insurance claims and plans for remarriage. At the scaffold on March 24th, 1873, she suffered a botched hanging, her body convulsing at the end of the rope for three minutes.