When Robert Blake left his wife in Birmingham and together with his two children moved in with his long-time mistress, Harriet Parker, in St. Luke’s, east London, he laid down his terms unequivocally.

“I intend to sleep around as much as I like,” he told Harriet. She evidently didn’t think much of that, because when he went off on his own to a party on New Year’s Eve, 1847, she followed him. She caught up with him at the Duke of Bedford pub, where he began taunting her in front of his mates.

“I’ll get my own back, you’ll see!” Harriet cried. The men laughed. They had heard her say it all so many times before.

She left the pub and at four o’clock in the morning went to a neighbour’s house. “I’ve done it!” she exclaimed. “I’ve got my own back. I’ve suffocated his kids in their bed. I’ve killed them both.”

When the constable arrived Harriet said: “I planned it. I hope I’ll be transported for life.”

A worse fate than that awaited her. She was sentenced to death at the Old Bailey and hanged on Tuesday, February 22nd, 1848, outside Newgate Prison “before an immense crowd which behaved badly.”

A newspaper report observed: “The wretched woman’s struggles were for some time dreadful in the extreme.”