The 25-year-old punched one man up to 20 times and left a 16-year-old boy with broken teeth, Liverpool Crown Court was told.

Despite the assurances of his club manager Kevin Keegan that Barton is a changed man, Judge Henry Globe, who lifted reporting restrictions, sent him to jail.

The judge described him as "aggressive and disgraceful".

A statement from Barton's club said: "Newcastle notes the sentence passed to Joey Barton at Liverpool Crown Court.

"The club is considering the verdict and will be making no further comment at this moment."

Barton, cousin Nadine Wilson, 27, and brother Andrew Barton, 20, were captured on CCTV in a number of violent incidents in Liverpool city centre during the early hours of December 27 last year.

It took place as Barton was on bail for an alleged assault of former Manchester City team-mate Ousmane Dabo, 31, and a separate criminal damage offence.

At around 5am the player, who had been on a night out with Wilson and his brother and had consumed 10 pints of lager as well as other alcoholic beverages, led his group into a McDonald's restaurant.

Once inside, the court heard, "loud and aggressive" Wilson, who had drunk up to three bottles of wine, became involved in a confrontation with a group of youths.

Outside the restaurant, the rows continued and Barton was caught on CCTV knocking an unidentified man to the ground.

He then straddled the man, and punched him four or five times as Wilson threw food at the victim before Barton punched him up to 15 times more.

Minutes later, the player attacked 16-year-old Jordan Spencer, punching him in the mistaken belief the youth had slapped Wilson.

The punch broke a number of Mr Spencer's teeth and, as it took place, a member of Barton's group was shouting: "Stamp on him, Joey, stamp on his head."

Wilson and Andrew Barton also became involved in the violence.

Ian Harris, prosecuting, described the incident as "violent and cowardly".

He said: "None of the victims were physically intimidating or threatening. In fact, they were backing away."

The court was told the Barton brothers had been goaded by remarks about their stepbrother Michael, who is serving life for the racist murder of Anthony Walker in Huyton, Merseyside, in 2005.

Stuart Driver QC, for Barton, said his client had been subjected to "truly obscene" references to his step-brother by other city centre revellers.

He said: "They associate him with it and feel free, when drunk, to throw it at him.

"Minutes of build-up led to a few seconds of violence."

In his character reference, Keegan described how he first knew Barton when he was the Manchester City manager.

He said: "Had I been asked to give character evidence for him then, I probably would not have been able to do so."

But Keegan then said there had been a "massive change" in Barton, adding: "He has taken stock of his life, he is more thoughtful in his actions and character.

"He is a far more responsible individual."

Peter Kay, of the Sporting Chance clinic in Hampshire, which has been supporting Barton since January, said the player had an alcohol problem.

Mr Kay said: "Joey recognises he has an addiction to alcohol and the only way forward is total abstinence."

Judge Globe told Barton: "Without doubt, the most serious of the three offenders is you.

"You were restrained by others but ignored them and acted in an extremely violent and aggressive manner.

"It also happened at a time when you were on bail for two other matters. If ever there was a time when you should be on your best behaviour, it was then.

"You have a high profile as a footballer and you know that draws attention to you. Yet you drank to excess and behaved in an aggressive, disgraceful manner."

Barton, of Foxbank Close, Widnes, was jailed for six months for actual bodily harm and four months concurrently for affray and ordered to pay £2,500 compensation to Jordan Spencer.

Wilson, of Childwall, Liverpool, was given a six-month sentence for ABH and two months for affray, suspended for two years.

She was also given a 12-month supervision order and instructed to carry out 12-months unpaid work.

Andrew Barton, also of Foxbank Close, Widnes, was given a four-month sentence for common assault, suspended for two years, and a 12-month supervision order.

Joey Barton will appear at Liverpool Magistrates' Court on May 30 to face trial for an allegation of criminal damage.

He also will stand trial at Manchester Crown Court in June for the alleged assault of Dabo.