A violent teenage gang leader has been jailed for six years for a mugging in which the victim was “stamped on like a cockroach”.

Cyrus Pinnock, who was already serving time in jail, was found guilty of robbery and wounding with intent to cause grievous bodily harm in August.

Pinnock, 19, led the G Block gang which police believe were responsible for more than 100 robberies in Tooting and Wandsworth.

At Kingston Crown Court on Wednesday, Judge Price said his sentence would be served concurrently (running at the same time) as the seven years he received for the conspiracy rob charges.

But, he added, a public protection order would mean he could only be released if no longer deemed a public threat.

Speaking outside court, Detective Sergeant Phil Booth, of Wandsworth police, said: “We are very pleased with the result. His incarceration will keep the streets of Wandsworth safe.

“It’s down to a good team effort by members of the robbery squad in Wandsworth who were based there between October 2007 and June 2009.

“It’s to their credit and their hard work that they got this result.”

At the trial Pinnock was found guilty of robbing and wounding Andrew White with three others on October 13, 2007, near Garratt Lane.

Mr White was set upon by four youths on the corner of Iron Mill Road and Borrodaile Road, where witnesses saw him being beaten with a metal bar and a knife.

His wallet was stolen and the youths tried to obtain his pin number, but he was already unconscious.

A source at the time said the assailants were “trying to annihilate him”, stamping on him “like a cockroach they wanted to kill.”

Police believe Pinnock learned his trade from the three other attackers while he was living in Elliot Court, near Southside Shopping Centre.

In 2004 he moved with his mother to Tooting and formed his own street gang named after Gearing Close, where he lived, but kept strong links with the Wandsworth robbers.

He recruited seven other boys during football coaching sessions on Tooting Bec Common, one of whom was just 13-years-old.

Together they went out at night in balaclavas and masks, armed with knives and mallets, mugging mainly young professionals between July and December 2007.

When they were arrested, police seized Pinnock’s computer and found internet conversations with fellow gang member, predicting that he would be on the news for attempted murder after a mugging in Wandsworth.

The description of the incident matched the one involving Andrew White, giving police key evidence to prosecute.

Pinnock’s identity was revealed in August following a legal challenge from the Wandsworth Guardian.

Evidence is still being gathered against the other men involved in the attack.