A father who urged his nine-year-old son to poison his mother and frame her new partner for the murder has been jailed for 18 months.

The man from the Ilkley area – who cannot be named to protect his son’s identity – hatched the “diabolical” plot in more than 3,000 Facebook messages, a court heard.

The judge was told events took a sinister turn when the father began messaging his son in detail about poisoning his mother with nicotine.

He was a smoker and suggested he could extract it and it could be applied lethally to the her skin.

The man suggested to his son that his mother’s new partner could be implicated by putting one of his hairs in the jar of poison.

The man told his son it would “kill two birds with one stone.” He allegedly added: “I’d do the lot of them if I could.” He pleaded guilty to theft, fraud and perverting the course of justice.

A charge of encouraging or assisting in the commission of causing grievous bodily harm was dropped.

Judge Jonathan Rose said he was satisfied the man did not intend to kill or seriously injure the woman.

Prosecutor Kitty Taylor said the man wanted his son, who resides in Bradford, to live with him after his relationship with the boy’s mother ended and she met a new partner.

Between June and September last year, he maliciously incited the boy to steal. The man got the child to steal his mother’s bank card and pass on her pin number. He withdrew £300 from her account after telling his son to hide the stolen card under a rock.

“It was punishment to her from an embittered ex-partner,” Mrs Taylor said.

The boy was torn between two parents, Bradford Crown Court was told.

His father secretly handed him a phone with a password and met up with him at school without his mother’s knowledge.

Judge Rose said the man vented his anger, malice and hatred on the boy’s mother, who had never tried to stop him seeing his son.

“I use the word reprehensible. It is unforgivable,” the judge told him.

It was cruel to the child to make him keep secrets from his mother and he was left hurt, harmed and damaged.

The prison sentence reflected “the public horror that a man could act in such a despicable way to his own son.”

The defendant’s lawyer, Ian Hudson, conceded they were “disgraceful, despicable, diabolical,” offences from a “bitter, spiteful and angry” man.

His remand in jail had been a horrific experience. He had learned his lesson and was deeply ashamed.