A drink and drug-fuelled knifeman who brutally murdered a “devoted and generous” dad-of-three outside a village pub has been jailed for life.

William Cosier will have to serve a minimum of 25 years before he can apply for parole for the fatal stabbing of Adam Pritchard, who was described as “the light” of his parents’ lives.

Cosier, known as Billy or Bill, was said to have been “off his head” shortly before the killing, having spent several hours drinking and snorting cocaine at The Queen’s Head in Boughton-under-Blean on March 13 this year.

That night, Mr Pritchard, a painter and decorator from Faversham, had been warned in a series of WhatsApp chats with one-time friend Craig Brabon - who was with Cosier - that if he went to the venue he would “get hurt.”

The conversations were said to veer between “friendly banter” and arguing, and at one point Mr Brabon, who had previously fallen out with Mr Pritchard, said he would not be able to stop Cosier if he turned up.

But Canterbury Crown Court heard the 35-year-old ignored the advice, saying he wanted a beer, only to be fatally stabbed within five minutes of his arrival.

Having initially walked into the bar and exchanged punches with Cosier, Mr Pritchard retreated back outside.

It was there, after goading Cosier into the street, that the violence escalated, with Mr Pritchard firing a BB gun multiple times and Cosier plunging a knife, which he had grabbed from the pub kitchen, “up to the hilt”, said the prosecution.

It penetrated Mr Pritchard’s ribcage to a depth of almost 23cm, causing liver and lung damage and leading to his eventual collapse and ultimately death at the roadside.

Cosier fled the scene, abandoning his Mercedes car in nearby Colonels Lane, before handing himself in to police the next day.

The knife, which was taken after the stabbing by another customer, was never recovered.

Cosier, who has previous convictions for violence and in 2017 was jailed for illegally possessing a Beretta, 20-bore shotgun, had denied murder, claiming to have acted in self-defence.

But the prosecution said extensive CCTV footage, coupled with his behaviour in the build-up to the killing, demonstrated he was “someone up for a fight and not afraid to stab someone”.

The 34-year-old was found unanimously guilty by a jury of seven men and five women at the end of a three-week trial on October 9. He had also denied manslaughter.

Returning to court today to learn his fate, Cosier, of Well Lane, Fordwich, was told by Judge Simon James that he had been “intent on seeking and actively planning” a violent confrontation with someone who was effectively a stranger.

Furthermore, the judge said when the gun was fired at him, he was “oblivious to and unaffected by” the shots and went on to inflict the fatal wound.

“Although it seems Adam Pritchard was, like you, not just prepared for a violent confrontation but was seeking one, this was not in my judgement a case where there was any real necessity for you to go outside at all,” he told Cosier.

“I find myself forced to the conclusion that you were an aggressor and willing participant from the start and that when you left the pub with the knife hidden behind your back, you intended to use it as a weapon.”

Mr Pritchard’s family had been present throughout the trial and a victim impact statement written by them was read out at the sentencing hearing by his brother, Gareth Pritchard.

Addressing Cosier by name, he described how his “senseless” murder of a man who was loved by many and “the person you could always count on” had left them “heartbroken with a constant ache”.

“Adam was the light of our parents’ lives, their pride and joy, and source of happiness and hope,” he said. “No parent should have to bury their child.”

He also spoke of the “deep loss and uncertain future” now faced by Mr Pritchard’s devastated fiancee and young family, including his two daughters and a son who is not yet a year old.

“We all as a family seek justice for Adam. We are in desperate need for closure and peace,” continued the brother.

“You, William Cosier, have left us feeling heartbroken with a constant ache and struggling to find the point of anything in this world which is so much darker without Adam.

“You have never said sorry, you have never taken accountability, you have never shown any remorse. You have made our family have to relive this nightmare in a courtroom and we will never forgive you.”

Concluding that whatever sentence imposed would never be enough, Gareth Pritchard added: “We hope you feel the pain, hurt and emptiness we have for the rest of your life.”

In his sentencing remarks, Judge James said "whatever faults" the victim may have had, he was a much-loved family member whose "kindness, humour and generosity touched so many".

He also told Cosier that he bore responsibility for the "pain and immeasurable anguish" they now felt at the "untimely" death, having chosen to become directly involved in a dispute between Mr Pritchard and Mr Brabon.

Judge James also dismissed the claims that Cosier had been scared of the victim, referring to him throwing the first punch in their initial scuffle and then "purposefully marching" to the kitchen to grab what would be the murder weapon.

He told Cosier: "On my assessment of the evidence, you made a conscious and deliberate decision to take a knife to what you knew was inevitably going to be a violent confrontation to use it as a weapon."

But having accepted there may not have been a "premeditated" intention to kill, Judge James added: "The inescapable truth was that you were both not only prepared to fight but willing and armed to do so.

"But whereas you ended up with relatively superficial injury, he was senselessly killed."

At trial, Cosier told jurors he had no intention of even hurting Mr Pritchard when they came face-to-face in the street.

But CCTV footage from the pub kitchen showed him chatting to staff earlier in the evening about how to stab someone in the ribcage, and then later ignoring the landlady’s desperate pleas as he armed himself with the murder weapon.

He had also been captured on pub cameras taking another knife from the staff area and stuffing it down the back of his trousers before Mr Pritchard had even arrived.

However, that blade had been retrieved by a customer ahead of the fatal stabbing.

The murder was, said prosecutor Don Ramble, “an act of aggression”, borne out of the phone conversation between the victim and Mr Brabon, which had escalated from “friendly banter” to gun and knife violence.

Although Cosier and Mr Pritchard did not know each other, they also spoke that night on the phone for several minutes in what was said to be an “aggressive” call.

Having arrived at the pub in The Street shortly before 1pm, Cosier had on his own admission consumed about six pints of San Miguel, “some” whisky and five or six “pinches” of cocaine by the time of the brutal killing.

Mr Pritchard, who was described by his partner as “kind, generous and with a heart of gold”, had been drinking at home and so asked a friend, Leigh Bean, to drive him there.

But they had only been at The Queen’s Head for approximately four minutes when the fatal wound was inflicted at 10.39pm.

After the initial exchange of punches and Cosier then arming himself, the two men became embroiled in the confrontation outside.

Cosier could be seen on CCTV hiding the large blade behind his back.

But it was as a fight erupted, spilling across the road, that multiple shots rang out from the gas-powered gun and the fatal knife wound was inflicted.

A mobile phone audio recording of the commotion outside had also captured Cosier threatening “I’ll kill you. You’re dead..”

While he was left with metal gun pellets in his head, neck and arm, a heavily bleeding Mr Pritchard was left mortally wounded.

Still clutching the gun, he had initially fled down the street, before trying unsuccessfully to get back into the pub.

He eventually collapsed in the street, whereupon he was dragged into his Peugeot car by Mr Brabon and Mr Bean.

Numerous 999 calls had been made, including one by the dying man himself, but the pair drove Mr Pritchard away from the scene before the emergency services had arrived.

En route to hospital, they flagged down an ambulance but his life could not be saved and he was pronounced dead by paramedics a few minutes past midnight.

The gun, bloody from having been held against his wound, was later found by police in the car boot. Although classified as a firearm, it did not require a licence to own.

Cosier, who is also a dad of three and had been due to gain custody of his children within days of the murder, has been in prison since his arrest.

It was argued that his actions that night were initially defensive and there had been no intent to kill.

Jonathan Higgs KC, defending, dismissed his earlier behaviour with staff in the kitchen as being “drunken foolishness and banter.”

Furthermore, he said the court could not ignore the fact that Mr Pritchard had gone to the pub “with purpose and with a loaded firearm” and had then goaded Cosier out into the street.

Mr Higgs also argued that once the two men had “disengaged”, there had been no pursuing of Mr Pritchard.

The court heard that while in prison Cosier had been diagnosed with PTSD as a consequence of that night

Referring to a letter he had since written, Mr Higgs added: “He makes reference to his regret but doesn’t express remorse - it would be odd and rather hollow if he did.

“But he does express his regret that it has occurred and the shocking impact it has had.”

During the trial Mr Brabon was not called to give evidence for either the prosecution or defence.

During the trial it was reported on KentOnline that pub landlady Claire Hammond-Miller had spotted Adam Pritchard was holding a gun after being stabbed and had locked him out.

We are happy to clarify that while Mrs Hammond-Miller described in her police interview the reasons why she could not let Mr Pritchard back into the pub, it was two other individuals who closed and locked the door as Mrs Hammond-Miller stepped back. We apologise this was not made clearer.