Mihai Avramescu, 29, was riding his Yamaha scrambler bike in Ladybridge Drive, West Hunsbury, when he lost control while overtaking a car, skidded and crashed.

He was wearing a crash helmet and ran off, but his pillion passenger, 26-year-old Ryan England, was not. He suffered fatal injuries and died at the scene at about 5pm on April 20.

Northampton Crown Court heard yesterday how Avramescu, who is originally from Romania, was a banned driver and the bike was not suitable to be used on public roads.

Martin Pinfold, prosecuting, said: "The precise cause of the accident is not exactly clear but the expert examiner suggested it could have been as a result of the pillion passenger losing his balance or position, as the absence of foot rests could have been a contributory factor, impairment of the rider, or a combination of the two."

Passing sentence, Judge Richard Bray described it as a tragic case, adding: "There are a number of aggravating features. You had been driving around this estate for some time with witnesses describing your driving as fast, reckless and aggressive, clearly in excess of the speed limit. This vehicle should never have been on the road."

The court heard the motorbike's tyres were not suitable for road use, it was not taxed nor had a valid MOT certificate, there were no rear foot rests and Avramescu was serving a three-year ban for drink-driving.

Judge Bray added: "The matter is further aggravated by the fact you ran away, leaving your passenger dying on the ground. There must be a substantial sentence."

Avramescu, of Cissbury Road, Briar Hill, Northampton, pleaded guilty to causing death by dangerous driving, failing to stop after an accident, driving while disqualified and driving without insurance. He was jailed for six years and disqualified again until 2015.

Steven Evans, defending, said: "This is a very chastened and sad young man.

"His biggest punishment will be living the rest of his life knowing he was riding the motorbike when a very good friend died."

Mr England's family raised more than £3,000 for the Northamptonshire and Warwickshire Air Ambulance, as paramedics tried to save his life after taking just eight minutes to get to the crash scene.