A court has heard a heartbreaking account of how a man's life has been turned upside down by a thug's single punch attack in Whitehaven.

Graeme Clarke suffered a devastating brain injury in the unprovoked attack.

At Carlisle Crown Court, Judge Peter Davies jailed the man responsible - 35-year-old father-of-four Paul Gunn.

Prosecutor Kim Whittlestone outlined how the victim was having a night out with his brother in Whitehaven town centre on August 13 last year.

At the end of the evening, two men became involved in a minor confrontation with Mr Clarke's brother on Lowther Street.

"There was some pushing and shoving, but no serious violence," said the prosecutor.

Gunn and another man were nearby and despite having nothing to do with either party the defendant intervened, confronting Graeme Clarke's brother, said Miss Whittlestone.

"Graeme Clarke moved away from the group and appeared to be on his mobile phone," said the prosecutor.

A witness who lives nearby reported seeing Mr Clarke on his phone, and she confirmed that he was not in any way being aggressive. CCTV images which captured what happened confirmed this.

"The defendant then walked up to the victim and punched him with significant force to the face," continued Miss Whittlestone.

Mr Clarke fell like a dead weight to the ground, unconscious. He underwent emergency brain surgery at a Newcastle hospital, remaining in an induced coma for 48 hours.

Part of his skull had to be removed so that surgeons could repair a life-threatening brain bleed.

In the months since the attack, Mr Clarke has battled to recover, suffering memory and language problems, anxiety, and mood swings. His mobility had also been affected.

For a time while he was in hospital he could not even recognise his father.

"I was angry about what happened to him," said Mr Clarke, speaking of the impact on his father and the rest of his family.

"My father saw me lying on the pavement, not knowing whether I was alive or dead. My family had to cope with my lengthy stay in hospital, not knowing whether I would survive... I hate looking at myself in the mirror.

"I am not the person I was before... I have no happiness. I live in fear. I don't know how long this will last for, or if I will get back to being the person I was before the attack."

Mr Clarke has not been able to work since the attack. He was often unable to sleep, and even his sense of taste had changed, he said.

Gunn, of Thornfield Close, Cleator Moor, admitted a single charge of inflicting grievous bodily harm.

His barrister Michael Davies said the defendant had stayed at the scene to help his victim once he realised how seriously hurt Mr Clarke was.

The barrister said references spoke highly of Gunn, a father-of-four.

"He wasn't looking for trouble that night," said the barrister, pointing out that Gunn felt deep remorse. Mr Davies added: "He got it wrong; he got it badly wrong and he is horrified by the injuries that have happened."

Passing sentence, Judge Peter Davies told the defendant, who was drunk when he punched his victim: "You punched Mr Clarke to the face. There is CCTV of the incident and it shows an bit of an altercation, a momentary pause, at which point you step forward, and punch - punch hard."

Mr Clarke plummeted to the ground, said the judge.

Judge Davies continued: "Although it's correct to say it's one blow, the impact on him was truly catastrophic. Sometimes, one punch can cause somebody's death - especially in the street, where they are unprotected, and land on concrete, or stone.

"He went to hospital in Newcastle, and had surgery, and part of his skull removed; he had a bleed on his brain, and was in an induced coma for 48 hours."

Now, Mr Clarke's life had been changed, possibly irrevocably, said the judge.

He judge added: "You can't ignore the catastrophic harm which is caused to somebody in cases like this... This is a very troubling case. It might be said that there was only one blow and there should be a trivial sentence.

"But the impact of what you did, the brutality of that punch, and the injuries it caused, drive me to impose your first custodial sentence."

He jailed Gunn, who was supported in court by family members, for 32 months.