A man who attacked a phone executive with a bottle at a south London event where singer Jessie J was performing has been found guilty of murder.
Ashley Charles, 26, was at the bar at Pulse nightclub when he grabbed a bottle from 37-year-old Phillip Sherriff's hand and slashed his neck.
At the Old Bailey, Charles, of Nevanthon Road, Leicester, was given a life sentence and told he will serve a minimum of 14 years.
The graphic designer had denied murder.
The attack happened at the bar at Pulse nightclub in Southwark, south London in April.
Charles claimed he acted in self-defence but Judge Paul Worsley said Charles killed Mr Sherriff, a telephone executive from Preston, Lancashire, because he was annoyed.
Father-of-two Mr Sherriff had travelled to London with colleagues for the promotion event organised by mobile phone company Blackberry, for which he worked.
Jurors heard Charles had travelled to London from Leicester with his brother and friends to attend the event.
Judge Worsley told Charles: "Mr Sherriff may have pushed you in a crowded bar and made inoffensive remarks to a girl talking to you.
"You clearly became annoyed at what you perceived was the conduct of Mr Sherriff and lost your temper when he may have pushed against you at the bar."
Charles grabbed a bottle from Mr Sherriff's hand, swung it behind him, breaking it, and slashed his neck.
The judge said Charles had done something "which was truly out of character".
"I am satisfied you did not intend to kill Mr Sherriff and you were immediately remorseful," he said.
Andrew Hall, defending Charles, said his client had acted "in a split second of madness".
The court heard Mr Sheriff died four days after the attack.
A post-mortem examination gave cause of death as a stab wound to the neck.
Duncan Penny, prosecuting, said the clash came just after midnight once the performers had left.
As people tried to help Mr Sherriff, Charles was detained by security staff.
The court heard he asked them: "Is he OK? I wish I had not done that. It was a stupid mistake."
And after being arrested by police the jury was told he said: "Yeah, I know I bottled him. He kept pushing past me through the bar area."
Mr Sherriff's wife Jane has launched a campaign to ban glass bottles from late night city centre clubs and pubs.
Speaking outside the court, she addressed Charles, saying: "I will never let another person like you devastate another family.
"Your actions have devastated so many people's lives."
Mrs Sherriff said organ donations from her husband had saved three other lives, but the lives of her family, including her two young children, had been ruined.
In a statement, she said: "I have always known that whatever the outcome today, nothing will fill the massive hole left when my husband Phil was so brutally taken away from us.
"However, I'm glad that justice has been done."
Det Insp Richard Beadle, the senior investigating officer in the case, said: "I hope his conviction will bring some sense of justice to the family who have been devastated by Phillip's murder.
"He truly was a decent, hard-working family man who in no way contributed to his own demise."