Stephenson had been described by the UK law enforcement circle as an ‘untouchable godfather.’
The Nigerian was one of 18 men indicted in the supply of guns and ammunition, following a West Midlands Police investigation, according to www.ibtimes.co.uk.
He was handed his sentence on Thursday after a police operation exposed him as one of the city’s most prolific illegal firearms dealers.
An undercover police operation, conducted over a number of months, saw police intercept the movement of weapons from suppliers to buyers on five separate occasions.
In total, 14 men were implicated in the sale of the deadly weapons after a police sting set up in 2014 by the force’s Serious and Organised Crime Unit with support from the National Ballistics Intelligence Service.
Among those convicted were Fitzroy Ducram, 50, (seven years and four months); Rowan Gul, 33, (12 years and three months); Louis McDermott, 36, (nine years and four months); Theodore Wiggan, 28, (10 years); and Sundish Nazran, 32, (13 years).
Stephenson and his gang provided firearms and bullets to other criminals, including those similar to the murder weapon attributed to the Aston shootings, which left two teenage girls dead at a New Year party in 2003.
Letisha Shakespeare, 17, and 18-year-old Charlene Ellis died in a hail of bullets fired from a MAC-10 machine gun.
Police Chief Inspector, Simon Wallis, of the West Midlands Police’s Serious and Organised Crime Unit, said, “Stephenson, aka Nosa, was widely-regarded as the untouchable ‘godfather’ of the Burger Bar gang, but as this case goes to show, nobody is above the law. He was at the centre of this highly-organised and extremely dangerous gun supply network.”