Daniel Boulton travelled 28 miles on foot from Skegness to Louth, Lincolnshire, in order to kill his former girlfriend Bethany Vincent and her nine-year-old son Darren Henson at around 8pm on May 31 last year.

Lincoln Crown Court was told Boulton, who was the subject of a restraining order following a complaint by Ms Vincent, developed a “hatred” for Darren and “loitered for hours” outside their home in High Holme Road before the killings.

Boulton tried to claim he was on “autopilot” at the time of the murders, but jurors dismissed his defence of loss of control.

The 30-year-old killer admitted manslaughter on the second day of his trial, as well as assault with intent to resist arrest, and burglary, but denied murder.

Boulton, of Alexandra Road, Skegness, will be sentenced at the same court on Wednesday.

Thanking the jury for their service on the difficult and “extremely distressing” trial, the judge said: “You have with great calmness listened objectively to the evidence, the arguments and the legal directions.

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“For that you have my very sincere thanks.

“The case you have had to deal with has had real horrors.

“I will direct that you each be written to and be formally excused from jury service for a period of five years.”

After Daniel Boulton was convicted of both murders, Mr Justice Pepperall told the prosecution and defence barristers: “I don’t see the need for any further reports in this case.

“My intention would be to pass sentence tomorrow, which will give me an opportunity for proper reflection and also for me to consider sentencing notes, which I hope you will be in a position to prepare for me."

Daniel Boulton trial: Man who murdered ex-partner and her autistic son had developed 'hatred' of the nine-year-old boy