lucky punch is not a term used by the judge or legal profession, it is 'one blow manslaughter'.
Here's some background on sentencing
"The appellant and Mark Skelton, the man who was to die, were good friends. The appellant was aged 26, and Skelton 28. The appellant lived with a woman called Louise Tchaikovsky and three children. The two younger children were their own and the eldest was a child by another man.
The appellant and Skelton were working together on rebuilding the appellant's patio. In the late afternoon they had a couple of cans of lager and then early in the evening they went out together for a night in Rotherham town centre. In the course of the evening they each consumed in the region of eight to ten pints of lager, possibly more. Skelton became a little the worse for wear and the appellant took him back to his home, arriving there shortly before midnight. They then relieved a relative of Louise Tchaikovsky who was baby-sitting. The baby-sitter was needed because Louise had also gone out for a night on the town with her younger sister Leanne, who was aged 17, and some of their mutual friends. They, too, consumed a fair amount of alcohol.
Louise returned home at about 2.30am. She found the appellant and the deceased soundly asleep each on his own sofa. She tried to wake the appellant, but did not succeed. She managed to wake up Skelton, who suddenly kissed her on the lips. She was upset and said, "What have you done that for?" and pushed him away. She left home in some distress, telephoned her sister Leanne to tell her what had happened, and made her way to Leanne's house. Leanne stormed round to the appellant's home to find Skelton and the appellant asleep. Not without some difficulty, she succeeded in waking up Skelton. She launched a frenzied attack on him, punching and slapping him in the face. The appellant then woke up. Leanne gave him some kind of account of what she understood had passed between Skelton and Louise. The appellant got up and went into the kitchen. Skelton followed him. At this time it seems that he did not accept that he had done anything inappropriate. This caused Leanne, who followed them into the kitchen, to telephone her sister on the mobile phone. Whether either of the men spoke to Louise on the telephone is not clear, but it seems that at this point Skelton said that he was sorry. The appellant then grabbed hold of Skelton's shirt with his right hand and hit him once on the right cheek, using his left hand. Skelton collapsed to ground. This single blow had caused a traumatic subarachnoid haemorrhage, that is the bursting of a blood vessel in the brain, which had killed Skelton.
An ambulance was called. Whilst they were awaiting for it attempts were made to resuscitate Skelton, in which the appellant assisted with mouth-to-mouth resuscitation"
The judge said:
"Cases such as this can present a difficult sentencing exercise. In mitigation are your character, your early plea, your remorse and the fact that the violence was limited to the one punch. Against that is the background of excessive drinking, without which this incident would probably never have happened at all. At the time you struck your victim he was doing nothing at all to you, and there was no possible justification for the use of any violence; and, of course, the fact that death resulted shows why courts must always take a serious view of any unlawful violence because unintended results are always possible. "
"There has been a recognition in recent years that too little attention was sometimes paid in the past to the fact of loss of human life, and in my judgment that must be right. Causing the death of another human being by unlawful violence must result in a sentence of some length"
And he was sentenced to three years.
The Court of Appeal however ruled that this was excessive, saying
"There were mitigating factors. The appellant struck a single blow of moderate force. He showed responsibility after Skelton fell to the ground in assisting in attempts to resuscitate him. There is no doubt of his remorse. He had killed a close friend. He has the benefit of a guilty plea made at the earliest opportunity.
We turn back to Coleman. We can see no reason on the facts of this case to go beyond the recommended starting point of twelve months. Accordingly, we quash the sentence imposed and substitute a sentence of twelve months' imprisonment."
www.bailii.org/ew/cases/EWCA/Crim/2005/3147.html