Mary Blandy was the daughter of Francis Blandy, a prominent figure in Henley being both a wealthy lawyer and also the town clerk.

Her father hoped that Mary would be able to marry well, and reportedly offered a generous dowry of £10,000 (over £2 million today) to the man who would marry her.

This offer may have been a mistake, as it attracted one Captain William Henry Cranstoun, son of a Scottish nobleman. The relationship led indirectly to Francis Blandy's murder.

Mary met and began courting Cranstoun in 1746 when Mary was in her mid 20's, even moving into the Blandy household for over a year.

It was at this point that the Blandy's discovered Cranstoun's dark secret: he was already married, and had been since 1744.

Cranstoun denied that the marriage had been legitimate, and even travelled back to Scotland a number of times to try and get the marriage officially annulled.

However, by 1751 Francis Blandy's patience with the young man had run out. He began to see Cranstoun as the philandering gold-digger he appears to have been and threw Cranstoun out of his house, forbidding Mary to continue seeing him.

Mary however appears to have remained completely under Cranstoun's spell, and Cranstoun wasn't going to let the £10,000 slip out of his grasp so easily.

Cranstoun showed Mary some white powder, telling her it was a 'love philtre' which would soften her father's heart and allow them to be together. It was down to Mary to get her father to consume the 'philtre'.

A few days later Francis Blandy became violently ill after eating some gruel that his daughter had given him. Some of the household servants who ate the gruel also became ill, though they recovered.

Her father wasn't so lucky. While he was sick in bed, Mary brought him tea laced with the same powder, making his condition worse.

When her father was close to death, he began to suspect Mary and accused her of poisoning him. Mary attempted to dispose of the remaining powder in a fire, but one of the servants managed to collect some and a chemist later confirmed that it contained arsenic.

Francis Blandy finally died on 14 August 1751.

Mary was immediately suspected of the crime, and kept on house arrest for a time, though later escaped across the river to stay with a friend at the Little Angel Inn at Remenham.

The law soon caught up with her and she was arrested. By this point, Cranstoun had made his escape, fleeing to France.

Mary Blandy's arrest and trial caused a sensation in England, partly due to Mary's status as a woman of wealth and means, and partly to do with the unusual facts of the crime.

Did Mary really believe what she claimed at her trial, that she was giving her father a harmless love potion? If so, did she not suspect that something was amiss when the household became ill?

Her trial lasted just one day, and the jury found her guilty of murder, with a mandatory sentence of death. After the trial, she was moved to the Oxford Castle prison, where unusually she was given 6 months in between sentence and execution.

Mary spend this time corresponding with a wide range of people, and writing her own account of the events which she titled "Miss Mary Blandy's Own Account of the Affair between her and Mr. Cranstoun."

These attempts to gain sympathy fell on deaf ears, and she was finally executed in front of a small crowd on 6 April 1752.

Mary's ghost is perhaps one of the busiest in all of Oxfordshire. She is supposed to haunt Brandy House the Little Angel Inn, the Oxford Castle at Westgate, Blandy House and the Kenton Theatre, as well as a number of other locations in and around Henley.