A graphic designer has been jailed for a minimum of 14 years for killing a telephone executive with a broken bottle after a Jessie J gig.
Ashley Charles, 26, was found guilty of murdering Phillip Sherriff, 37,at the Old Bailey.
Mr Sherriff died in April four days after being attacked at Pulse nightclub in central London, where the singer had just finished her performance.
Charles, of Nevanthon Road, Leicester, denied the charge, claiming he acted in self-defence.
But Judge Paul Worsley said Charles killed Mr Sherriff, of Preston, Lancs, because he was annoyed.
Judge Worsley told Charles: "This is a tragic case. 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 took a beer bottle from Mr Sherriff's hand and swung it behind him, where it broke, and then plunged it into Mr Sherriff's neck.
"It was a lethal weapon. He was a decent man," added the judge.
He said Charles had done something "which was truly out of character".
Judge Worsley told him: "You did not deliberately smash the bottle you used. I am satisfied you did not intend to kill Mr Sherriff and you were immediately remorseful."
Andrew Hall QC, for Charles, said he acted "in a split second of madness".
Mr Sherriff's wife Jane said in a statement to the court she had launched a campaign to ban glass bottles and glasses from bars and clubs.
Addressing Charles, she said: "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 saved three other lives, but the lives of her family, including her two young daughters, had been ruined.
Duncan Penny, prosecuting, told the trial Charles had been trying to get free beer at the promotional event organised by BlackBerry, the company Mr Sherriff worked for.
CCTV showed Charles grabbing the bottle and plunging it into Mr Sherriff's neck.
Mr Penny said: "It happened very, very quickly indeed - perhaps one second, one second to take a life."
Mr Sherriff began to bleed profusely as vital blood vessels had been cut.
Mr Penny said the clash came about just after midnight after Jessie J and other performers had left.
As people tried to help Mr Sherriff, Charles was detained by security staff. He asked them: "Is he okay? I wish I had not done that. It was a stupid mistake."
After being arrested by police, he said: "Yeah, I know I bottled him. He kept pushing past me through the bar area."