The wife of a factory supervisor hacked to death by two teenagers who tried to decapitate him with a samurai sword confronted the killers in court as she questioned: “How on earth have we come to this?”

CCTV footage, played in court on Wednesday, showed how Robert Wilson, 53, was investigating youths hanging around outside the Thornton and Ross pharmaceutical plant in Huddersfield when he was attacked by Kiyran Earnshaw, 18, and 16-year-old Luke Gaukroger, who passed the 20in sword between them.

Audio recorded from Mr Wilson’s phone call to a security firm captured Gaukroger – who was 15 at the time – shouting “get his head, I want to cut his head, Kia I want to cut his head”.

The recording, also played in court, captured the helpless night shift supervisor’s pleas to the youths to stop their attack.

Leeds Crown Court heard that Mr Wilson was married with two grown-up children and enjoyed gardening, golf and walking in the Yorkshire Dales.

His wife Elaine told the court his death was “completely incomprehensible”, adding: “How on earth have we come to this and why?”

She said she was sickened to receive a letter from one of the defendants saying it was the “worse night of my life and ‘I’m sorry'”. She told the judge she had been shocked to “feel so much hate”.

She said to the defendants: “I want you to know you have taken the life of a much respected, admired and good man.”

Peter Makepeace QC, prosecuting, told the court that Earnshaw started the attack after producing the blue sword from inside his tracksuit bottoms.

After he started raining blows on Mr Wilson, the younger teenager was heard repeatedly shouting: “Pass me the shank, pass me the shank.”

After multiple blows and kicks to Mr Wilson, Earnshaw passed the sword to Gaukroger, who can be identified after judge Mr Justice Lavender lifted reporting restrictions following a submission by the PA Media news agency.

Mr Makepeace said the pair paused at one point to catch their breath and to rifle through Mr Wilson’s pockets, taking his coat.

The prosecutor said that, after they resume the attack, “Earnshaw and Gaukroger together holding the sword and crouching to the upper body then seem to make a concerted effort to saw the head from the shoulders.

“Both then jointly stab the upper body using their combined force.”

Police who arrived at the scene reported seeing one of the pair “using the sword in sawing motion to the neck area of the deceased as if trying to detach the head from the body”.

Mr Makepeace said Earnshaw was Tasered twice before he was arrested and officers used an incapacitant spray on Gaukroger.

The court heard that Mr Wilson had left the plant to talk to the youths in the car park with colleagues Paul Thewliss and John Badejo.

Mr Badejo was seriously injured as he tried to help his friend and both men were forced to flee for their lives, Mr Makepeace said.

He said: “There is no suggestion they were anything other than polite and decent in their dealings with the youths once they met up in the car park.”

Both defendants admitted murdering Mr Wilson and Earnshaw admitted causing Mr Badejo grievous bodily harm with intent.

Mr Justice Lavender sentenced Earnshaw, of Field Lane, Batley, and Gaukroger, of Arthur Street, Huddersfield, to life with minimum terms of 22 years and 16 years, eight months respectively.

Mr Makepeace said the defendants were seen taking tablets “washed down with vodka and other alcohol” as they hung around Huddersfield with friends before the incident in January.

He said that, after his arrest, Earnshaw was slurring his speech, asking why he had been arrested and complaining of police harassment.

He told officers he had taken cocaine and the tranquilliser Xanax.

Tests on drugs Earnshaw had in his possession found they were Flualprazolam – an artificial substance similar to Xanax which produces drowsiness, confusion and disinhibition.

Sentencing the pair, the judge said: “As he lay dying, you used the sword in repeated attempts to cut off his head.

“You ended his life and you brought lifelong misery and grief to his wife, his two stepchildren and his other family and friends.”

The judge said: “This frenzied and senseless attack on a man who was quite unable to defend himself went on for about 10 minutes.”

He said: “I have watched the recording and it is a truly gruesome sight, made all the more ghastly by the fact that your blows and words, including your abuse of this dying man, and his attempts to speak, were being recorded, because he had begun a telephone call to the firm’s security company.”

The judge noted that both teenagers had committed offences of violence in the past.

He said this included an incident in October 2016 when Earnshaw used a knife to stab a fellow student at his school twice in the stomach.