A father-of-three was shot dead in the front seat of a car in a case of mistaken identity, a court heard.
Eddie Thompson, 29, was killed as he waited at traffic lights in Hackney, east London, in September 2009.
The intended target was sitting in the back of the car, jurors at the Old Bailey were told.
Kallum Morris, 18, and Paul Stoby, 18, both of Hackney, and Kieron Lawrence, 19, of Walthamstow, all deny charges of murder.
They also deny charges of possessing a firearm with intent to endanger life.
The court heard Arman Suleyman, who was the intended target, had let Mr Thompson sit in the front seat of the VW Golf as he was bigger.
Prosecution barrister Aftab Jafferjee QC said: "There was no evidence of him having any enmity with anyone that can explain why he should have been targeted for execution."
Mr Jafferjee said the seat change may have saved Mr Suleyman's life "but at the expense of Thompson".
A minicab carrying Mr Stoby and Mr Lawrence and a silver Vauxhall Corsa driven by Morris were seen behind the car, the jurors were told.
The court heard that when the VW Golf stopped at a set of traffic lights, Mr Stoby and Mr Lawrence got out of the minicab.
Mr Jafferjee said: "As Eddie Thompson sat in the front passenger seat with the window down, he was gunned down in broad daylight on a Sunday afternoon.
"A single bullet probably meant for his head but striking his upper left shoulder entered his chest cavity and killed him."
The jurors were told it was unknown who pulled the trigger, but prosecutors thought the three men were "in it together".
"Morris is the man with the motive and the recruiter," Mr Jafferjee said.
"Stoby and Lawrence are the henchmen, each physically supporting each other in ensuring this high-stakes plan is executed with the minimum of disruption."
The court heard witnesses saw Mr Stoby and Mr Lawrence run to the nearby Pembury estate where Stoby lived.
The trial continues.