A jailed salesman who told customers he would kill them and burn their house down has had his prison sentence extended.

Cwmbran man Robert Knight, of Mountain Road, ran RK Transport on the Llantarnam Industrial Estate, Wales, and “would be pleasant and professional – until he achieved a sale,” prosecutor Lee Reynolds said.

Cardiff Crown Court was told of occasions when Knight would be asked to fix people’s cars after they had broken down or developed faults, sometimes just days after being bought.

But regularly he would launch into expletive-ridden tirades and tell people to get off his property or he would prosecute them, according to the South Wales Argus.

He told a couple that they “didn’t know what he was capable of” and that he would burn their house down and kill them after they complained about their new vehicle.

Knight (41)  pleaded guilty to 15 charges at the same court of engaging in unfair commercial practice and one count of supplying a dangerous product last June.

As the Argus has previously reported, father-of-seven Knight was already serving a three-year sentence for two sexual assaults on a teenage girl and an assault. He was jailed last month.