“We shall be happy to see you to dine with us today at half-past five o’clock,” said the invitation.

The recipient was Patrick O’Connor, a 50-year-old customs officer at London docks who also made a good living as a money-lender. The invitation was from Maria Manning, 28, a Swiss-born domestic servant who had been O’Connor’s girl friend but was now married. Her husband Frederick Manning was a former railway guard sacked after property began disappearing from his trains.

When the couple met, Maria was a maid working for the Duchess of Sutherland. Manning was unemployed but he was a glib liar, telling Maria he would come into a small fortune when his mother died. So Maria married him, tiring of O’Connor’s failure to propose despite being given every encouragement.

Manning had subsequently become a pub landlord and then an off-licence manager, losing both jobs through discrepancies in his accounts, and the couple were now living in reduced circumstances in Miniver Place, Bermondsey.

But Maria had not lost touch with O’Connor. She realised too late that he would have made a better husband than Manning if only she could have got him to the altar. For his part, O’Connor regretted losing the attractive redhead. He had since become a family friend, encouraged by hints from Maria that their old relationship might be renewed.

It was with this in mind that he accepted her invitation to dine with the couple on August 8th, 1849, and that was the last that was seen of him alive. The next day Maria called at his lodgings and expressed surprise that he had not returned home the previous evening. Shown to his room on some pretext, she quickly rifled his trunk, taking his French railway certificates but failing to find other bonds O’Connor had told her he possessed. Her husband sold some of the certificates later that day for £110.

Investigating O’Connor’s disappearance, police traced his last known movements to the Mannings’ home. Maria told them she was as puzzled as they were by her old friend vanishing.

When officers returned later to make further inquiries they found the house deserted. Maria had decided it was time to move and had sent her husband to arrange the sale of their furniture. While he was away she had left in a cab, taking everything she could carry. When Manning returned to find her gone he had panicked, taking a cab to Waterloo and catching the boat train for Jersey.

The couple had plenty to hide, as the police discovered when they searched the house. They found O’Connor buried in quicklime under the floor. He had been shot in the head and bludgeoned.

Maria was arrested in Edinburgh, Manning in St. Helier, Jersey, and at their Old Bailey trial they accused each other of O’Connor’s murder. Both were convicted and condemned to death.

“There is no justice and no right for a foreign subject in this country,” Maria protested as she was sentenced. “There is no law for me. When I consider that Mr. O’Connor was more to me than my own husband, that I have known him for seven years, and that he has always felt the greatest respect and regard for me, I call upon you to think and consider whether it is likely that I should have murdered him.”

Addressing the judge, she continued: “I tell you, my lord, this verdict the jury have returned will rest on their conscience hereafter. I am not treated like a Christian, but like a wild beast of the forest. If I had wished to commit murder, how much more likely it is that I should have murdered that man” – she pointed at her husband – “who has made my life a hell upon earth ever since I have known him, than that I should have murdered Mr. O’Connor, who would have married me the next month after I became a widow.”

The couple were hanged together at Horsemonger Lane Gaol on NOVEMBER 13th, 1849, and on the eve of their execution Manning admitted his part in the murder. He said that Maria had shot O’Connor, exclaiming afterwards: “It’ll never be found out, as he and I were on such good terms. No one will have the least suspicion.”

When he told her she’d be hanged, Manning claimed, she replied, “I think no more of what I’ve done than if I’d shot a cat on the wall.”

When he went with her to view her handiwork, Manning continued, he saw that O’Connor was still clinging to life. “I never liked him,” he confessed, “so I battered his head with a ripping chisel.”