Adam was paid £25 a day for working on the site
A builder has been jailed for three years for the manslaughter of a boy who was crushed to death by a falling wall.
Adam Gosling, 15, from Latchingdon in Essex, had been left alone to prop up a wall in Hadley Wood, north London, in April 2007. He died from head injuries.
Colin Holtom, 64, also from Latchingdon, admitted manslaughter by gross negligence at the Old Bailey.
Contractor Darren Fowler, 47, from Upminster in Essex, was jailed for a year over health and safety breaches.
He admitted breaking health and safety law and running a company while disqualified from being a director.
Judge Christopher Moss told Holtom that he bore the "lion's share" of the blame for Adam's death.
The court heard Adam was earning £25 a day working with his older brothers at the site.
Adam died when he and brother Dean, 18, were given sledgehammers and a pneumatic hammer and told to bring down the unstable 7m (23ft) wall - without instructions.
Holtom has shown no remorse, the court was told
The judge told Holtom: "You adopted a cavalier and thoroughly irresponsible attitude to the brothers' safety.
"You simply left them to your own devices. Your actions - or lack of them - on that day were criminal."
The judge told the court that he suspected Holtom still regarded himself as "blameless" for the death.
In a victim's impact statement Adam's father, Mark, said: "Adam had his life stolen from him before it had started."
Mr Gosling said Holtom openly talked about the death in the village pub and had shown "no remorse".
Holtom, who was said to have a "laissez faire" attitude to health and safety and never provided equipments such as hard hats, had originally denied the offence.
He changed his plea last week as a retrial was due to begin.