A £9.7m National Lottery jackpot winner has been jailed for nine months after admitting affray and threatening teenagers with a baseball bat.
Michael Carroll was one of four people who attacked concert-goers
Former dustman Michael Carroll, 22, was sentenced at Norwich Crown Court, after he pleaded guilty in January.
Carroll and three friends barged into a Christian concert at Downham Market town hall in May 2004.
David Howard, 24 and his brother Paul, 19, were also jailed, while the fourth person has never been traced.
Richard Potts, prosecuting, told the court that trouble erupted when two girls, who are now aged 15 and 17, had punched another girl who had been at the concert.
Two of the concert-goers required hospital treatment.
Michael Carroll walks in armed with a baseball bat
Judge Peter Jacobs sentenced David Howard to 18 months, nine months for the affray and nine months for handling a stolen JCB.
The girls both received a one-year conditional discharge while Paul Howard was sentenced to six months in prison.
Sentencing Carroll and David Howard, Judge Jacobs said: "You went along to exact some form of retribution.
"A large number of people were terrified about what went on. This sort of behaviour cannot be tolerated."
The court heard that Carroll has 42 previous offences recorded since 1997.
On Friday, he told BBC Look East that he has spent £1.2m over the last few years on cocaine, but he now "deeply regrets" doing so.
He says he has not touched drugs for four months.
Interviewed in June last year, Carroll said he was changing his ways and that calling him a "lout" was wrong.
"I don't want to go back to prison," Carroll told a BBC journalist. "I have turned over a new leaf and want to get on the straight and narrow path."