A gangland assassin who fired on an innocent bypasser with a sub-machine gun, littering his head, torso, arms and legs with bullets, was convicted of murder yesterday.

Cem Duzgan was just 21 when he unwittingly became involved in the feud on October 5 2009, as he was playing pool with his friends in the Clapton FC Club, a Turkish social club in Upper Clapton Road.

The Old Bailey heard how the gunman Blaize Lunkula gained access to the club with the help of an accomplice, who held open a pair of secure air lock doors.

People inside became aware something was happening and when Mr Duzgan went to investigate the lobby area, Lunkula opened fire, shooting 11 bullets through his head, torso, arms and legs.

Ballistics experts later estimated that the weapon was closer than 30cm from Mr Duzgan’s head when it was fired.

Mr Duzgan, who lived with his family in Islington and worked as a sales assistant at a Croydon clothes store, died at the scene.

The court heard that the execution-style killing was part of a spate of violent tit-for-tat incidents - including other killings - that took place around that time between the Tottenham Turks and the Hackney Turks gangs.

Just three days before Mr Duzgan’s murder Oktay Erbasli was shot and killed in a targeted attack while he was driving a car in the Roundway, Tottenham.

The prosecution case was that Mr Duzgan was then killed in revenge, although he was not thought to be the intended target.

Acting Det Sgt Simon Franklin, the case officer for the Homicide and Major Crime Command, said: “The victim was simply enjoying a night out with friends when he went to investigate a disturbance.

“Sadly this decision cost him his life as he became unwittingly caught up in a bitter and violent rivalry between two Turkish gangs operating in the area.

“This has been a long and complex investigation linked to several other crimes and I am pleased at today’s convictions.”

He continued: “This will send a clear message that the streets of London cannot be ruled by fear and violence and that those who commit such offences and hide behind gangs will be brought to justice.”

Blaize Lunkula, 28, of no fixed address, was found guilty of murder, along with another three men who helped plan Mr Duzgan’s death - Yusuf Arslan, 24, Ndombasi Makusu, 27, and Christian Barabutu, 22, all of no fixed address.

Mobile phone analysis found that all the defendants had dumped their phones shortly after the murder and did not use them again.

The prosecution was able to produce evidence that Arslan had taken that time to call the brother of Oktay Erbaski immediately before and after the murder - when he reported that Oktay’s death had been avenged.

They will all be sentenced at the Old Bailey on 11 April.