The family of a university lecturer have branded his murderer a “deeply malevolent and thoroughly evil man” as he was jailed for at least 36 years following a campaign of physical and mental torture.

Sadistic church warden Benjamin Field, 28, killed Peter Farquhar, 69, in order to inherit his house and money after driving him to think he was losing his mind following a period of gaslighting.

Mr Farquhar’s brother, Ian, said Field “callously and greedily seduced his way into my brother’s life”.

“His sentence today brings some justice to this horrific event in our family’s life. Though of course the wound will always remain,” he said.

“Ben Field is a deeply malevolent and thoroughly evil man who callously and greedily seduced his way into my brother’s life.”

Mr Farquhar added: “My brother Peter was a loving member of our small family, a caring member of his community and local church, a hugely respected English literature scholar and teacher. He has and will be greatly missed.”

Detectives branded Field a psychopath and said he would have posed an “ongoing danger to society” had he not been stopped.

Oxford Crown Court heard Field secretly gave Mr Farquhar drugs and spiked his whisky, hoping that his eventual death at his hands would look like suicide or an accident.

It was only when the Baptist minister’s son began targeting Mr Farquhar’s neighbour, Ann Moore-Martin, in the village of Maids Moreton, Buckinghamshire, that his wicked scheme began to unravel.

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Benjamin Field was labelled a sadistic killer (Thames Valley Police/PA)

The sexually promiscuous Field also manipulated Miss Moore-Martin, a deeply religious retired headteacher, by writing messages on her mirrors purporting to be from God.

He admitted fraudulently being in relationships with the pensioners as part of his plan to get them to change their wills.

Mr Farquhar, who was torn about his sexuality because of his religion, died in October 2015 while Miss Moore-Martin died in May 2017 from natural causes.

Field underwent a “betrothal” ceremony with gay Mr Farquhar while also having a string of girlfriends and was in a sexual relationship with Miss Moore-Martin, who was 57 years his senior.

Prosecutors said Field had a “profound fascination in controlling and manipulating and humiliating and killing”, and alleged he plotted his crimes with his friend, failed magician Martyn Smith, 33.

The University of Buckingham PhD student was a prolific writer and had also drawn up a “100 clients” list of future targets.

Field, of Wellingborough Road, Olney, Buckinghamshire, previously pleaded guilty to defrauding Ms Moore-Martin of £4,000 to buy a car and £27,000 for a dialysis machine.

He also admitted two burglaries and the two fraudulent relationships.

Field insisted he had acted alone and not recruited his young brother Tom, 24, or Mr Smith to help with the dialysis fraud.

In August, the jury found Field not guilty of conspiracy to murder Miss Moore-Martin and the alternative charge of attempted murder. He was also found not guilty of possession of an article for the use in fraud.

Mr Smith and Tom Field were found not guilty of the charges they faced.

Maids Moreton murders
Church warden Benjamin Field admitted being in a fraudulent relationship with Ann-Moore Martin (Thames Valley Police/PA)

David Jeremy QC, defending, said two psychiatrists had said the defendant was either suffering from a narcissistic personality disorder or a psychopathic personality disorder.

“He was and is an intelligent and educated man and chose to apply those gifts towards the manipulation and humiliation of his victims, leading to the murder of Peter Farquhar and the degradation of Ann Moore-Martin and the causing of irreparable harm to their families and those close to them,” he said.

“The real motive was to make himself feel good about himself by deceiving and debasing others by being the only one who knew what he was doing, by gaining pleasure, not by sharing as others do, but by creating a world that only he inhabited, in which he was both performer and audience – the world of interiority.”

Maids Moreton murders
University lecturer Peter Farquhar was killed by Benjamin Field (Thames Valley Police/PA)

Imposing a life sentence, Mr Justice Sweeney said Field “lived by deception and deceit and had been a well-practised and able liar”.

“You further admitted how you could manipulate and manoeuvre people, however sceptical they may have been, to achieve your ends without ever asking them to do so directly,” he said.

“You were, you accepted, a snake talker, as you were able to build pressure on your victims to believe what you needed them the believe and then to do whatever you needed them to do.

“The evidence at trial clearly demonstrated grandiosity, a sense of superiority towards others, the exploitation of others to achieve personal gain, the need to belittle and humiliate others, fixation on fantasies of power and success, intelligence, a need for admiration from others, and a sense of entitlement together with an unwillingness to empathise with the feelings, needs and wishes of others.”

The judge said that Field murdered Mr Farquhar by covertly giving him drugs and getting him to drink strong whisky and then, “if it was necessary, finished him off by suffocating him in a way that left no trace.”

He added: “Like Dr Michael Alcock and Dr Philip Joseph, I have no doubt that you are a dangerous offender.”

Senior investigating officer Mark Glover, of Thames Valley Police, said: “This is unlike any other case I have investigated in more than 31 years of policing, and Ben Field is unlike any other criminal I have encountered.

“The extent of his planning, deception and cruelty towards his victims is frankly staggering, and I do not believe he has ever shown an ounce of remorse or contrition.”

The Diocese of Oxford said in a statement: “It’s clear that Ben Field manipulated everyone he came into contact with. We’re determined to learn what we can from this extraordinary case.”