Fans of the BBC's gripping new crime drama The Sixth Commandment are struggling to get their heads around the fact that its shocking events are actually based on real life.

The series, which is available to watch now on BBC iPlayer, stars Jon Bard and Anna Crilly, and tells the story of what happens in the wake of the deaths of Peter Farquhar and Ann Moore-Martin in the village of Maids Moreton, Buckinghamshire.

Viewers are treated to all sorts of twists and turns, and as a result it gets harder and harder to comprehend that this was a real British case.

Farquhar, played in the drama by Harry Potter actor Timothy Spall, was neighbours with Moore-Martin in Buckinghamshire.

BBC

They both worked in education, they were both religious, and they both found themselves victims of Ben Field, the Baptist minister's son, as he preyed on the older residents for financial gain and pretended he was in love with them.

Longing for companionship, Farquhar agreed to promise himself to Field in a 'betrothal ceremony' in the early 2010s, and welcomed him into his home.

Little did he know, Field began poisoning his tea, and after he began to struggle both mentally and physically Field convinced Farquhar to make him the main beneficiary of his will.

Field hoped his campaign of abuse against Farquhar would cause the elderly man to take his own life, but when that grisly plan failed to play out, Field suffocated Farquhar to death in 2015.

He left a half empty bottle of whisky close to his body, so it might look as if Farquhar had died from drinking too much.

Field was not initially a suspect in Farquhar's death, and he received £15,000 and half of Farquhar's house thanks to the altered will.

BBC

By that time, Field had already selected Moore-Martin as his next target. He managed to convince her, too, that he loved her, and moved into her home.

Once there, Field subject Moore-Martin to gaslighting and manipulation, including writing messages on mirrors which claimed to be from God and encouraged her to 'pray for Ben' and give him money.

Police became aware of Field's actions after Moore-Martin's niece, Anne-Marie Blake, had a concerning exchange with Field.

Moore-Martin had already changed her will to include Field, but after he admitted to having accepted money from Moore-Martin and taking things from her house, she changed it back.

Moore-Martin lived until 2017, when she died of natural causes in a nursing home.

It wasn't until after Moore-Martin's death that police launched a double investigation into Field.

BBC

Two years after Moore-Martin died, Field was found guilty of Farquhar's murder and sentenced to life in prison, with a minimum sentence of 36 years. He was cleared of conspiring to kill Moore-Martin and of her attempted murder, though he admitted to 'psychologically manipulating' both of Farquhar and Moore-Martin.

Fans of the series have been left baffled over the events, with one person commenting: "The Sixth Commandment is a truly chilling piece of television. It’s hard to believe that something like this actually happened - and not long ago too."

Another wrote: "Watching ‘The Sixth Commandment’ @BBCOne. Based on a true story, on the disturbing real-life case of Ben Field, who murdered Peter Farquhar and Ann Moore-Martin - after subjecting both to substantial psychological abuse while pretending he was in love with them. Stellar casting!"