Andrew Wanoghu, 26, was gunned down in the street after being lured to an address in south London in a trap organised by Delphon Nicholas in April 2006.
Nicholas, 29, and gunman Trevor Dennie, 33, were jailed for life at the Old Bailey today and told they must serve a minimum of 30 years.
Judge Richard Hone told the jury: "We have had an insight into what goes on in Belmarsh prison. It was a real eye-opener for us all."
Judge Hone revealed to the jury that the gun used in the murder had also been used in four other black-on-black Trident shootings.
And he told them of an "astonishing outburst" of violence by Nicholas in the dock while jurors were considering their verdicts.
He told the two defendants: "You are two cold-blooded killers.
"You exude an aura of violence. You are both extremely dangerous."
He said Nicholas had "orchestrated" the hit from his prison cell while Dennie had executed the plan by shooting the victim.
The judge said Nicholas would have to serve nine months which would have been deducted from his sentence for time served on remand because he had attacked co-defendant Sereata Barrie.
She was later cleared of murder with two other men.
The judge said Nicholas was now in the dock in handcuffs because he had punched and attacked her.
"Even by the standards of Court One at the Old Bailey, it was an astonishing outburst," he said.
Telling the jury about the gun, Judge Hone said: "It is a travelling gun, handed from hand to hand in the community which in circumstances like this, responds with a wall of silence."
Wanoghu and Nicholas were described by detectives as career criminals caught in the murky world of drugs and robberies.
Wanoghu had been accused of murder himself in 2002 following the shooting of Damian Cope, 24, outside a club in Holborn, central London.
He was cleared at the Old Bailey in 2004 after two witnesses refused to give evidence.
Anti-guns campaigner Lucy Cope pleaded for people to come forward with information about her son's murder but no one else has been charged.
Nicholas was on remand in Belmarsh having been arrested for firearms offences. The case was later dropped.
Wanoghu had been living in south London and had been friends with Nicholas until seven weeks before his death when he was said to have "dissed" Nicholas's father.
Wanoghu had "delivered a slight" to Nicholas by taking his father's car after punching him in the face, said Aftab Jafferjee QC, prosecuting.
Wanoghu, who was said to have a number of enemies, was shot in Brockley, south London. in April 2006,
Mr Jafferjee said: "He had been set up for execution."
Nicholas, from Sydenham, and Dennie, from Deptford, both south London, denied murder but were convicted yesterday.
After the case, Detective Inspector David Manning of Trident said the mobile phone used in the murder had been smuggled in from a lower category prison.
He said: "The phone started life at Wandsworth jail in September 2005 and transferred to Belmarsh by an inmate who handed it to Nicholas.
"The technology to block signals has been available for some time but it is illegal to use it at the moment.
"I hope this case will spur a change in the law. I accept there are problems, including blocking mobiles used by prison staff."
More than 3,000 mobile phones or sim cards were discovered in English and Welsh prisons between October 2006 and September 2007.
Prisons Minister David Hanson said: "The Government takes the threats created by mobile phones in prisons very seriously and we are committed to tackling and disrupting their use.
"Technology to detect mobile phones or block signals is currently being trialled and used in prisons."
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