A former public schoolboy who wanted to be a gangster was jailed for a minimum 30 years for murder today.
Rupert Ross, 30, disguised himself as a lawyer to gun down a rival outside Wandsworth jail in south London after getting caught up in the drug-dealing underworld.
He wrote in his diary that he was "living a gangster lifestyle, making good money and living a fast life".
But he was found guilty of murder at the Old Bailey on Tuesday, along with accomplice Leon St Aubin, a 34-year-old fireman.
Both men were jailed for life and each was given a 30-year minimum term.
Ross was from a wealthy background, with some of his family working as lawyers.
He had been a pupil at private Dulwich College but soon fell under the influence of drugs.
He had been in trouble with the police since he was 16 and had convictions for theft, burglary and drugs.
Stuart Trimmer QC, defending, said: "The previous convictions disclose a depressing cycle relating to drugs.
"He had the advantage of a good education, a loving family and a mother who spent time and resources to ensure he did well.
"He has been brought to where he now is as a result of the grip of drugs. It will blight his life and his family's lives."
But Judge Martin Stephens told the men: "You both carried out a well prepared and meticulously planned execution of a man who had become your enemy.
"You both dressed in what would pass as lawyer's clothes so you did not draw suspicion."
The judge said both had taken some steps to sort out their lives in recent times but "when a situation arose that you thought required revenge by killing, you carried out this monstrous attack".
Jurors heard Ross shot Darcy Austin-Bruce, 20, fives times outside the jail in May 2009.
Ross, of Fulham, west London, dressed smartly in a suit to blend in with lawyers paying visits to their clients.
He had been tipped off from inside the jail that Mr Austin-Bruce would be visiting someone inside.
After the shooting in front of visiting families, Ross was sped away on a stolen moped by Leon St Aubin, of Chelsea.
Crispin Aylett QC, prosecuting, said it was a murder of "breathtaking audacity".
He added: "To anyone who noticed him, the smartly dressed man must have looked like a lawyer making a legal visit to a client in the prison.
"There was, however, something slightly unusual about the man, in that he was wearing a crash helmet he had not removed from his head.
"This was, in the most literal sense, an inside job. The killers had been tipped off by someone inside the prison."
The shooting followed a falling out over a drugs deal and previous shooting incidents.
Acting Detective Chief Inspector Brian Lucas said after the case: "These men believed that they could get away with killing a man in broad daylight as revenge for a petty argument.
"I believe that they had lost sight of reality and now face the consequences of their sad and violent choices."