Colin Clarkson, aged 51, has been sentenced to ten years eight months with an extension of five years at Hull Crown Court for the attempted murder of a 19-year-old salesman who was at work selling energy contracts for First Utility outside the Asda supermarket in Grimsby.
Clarkson pleaded guilty to attempted murder and possession of an offensive weapon in a public place at an earlier hearing.
Jeremy Evans from the CPS said: “This was a brutal, random and completely unprovoked attack on the victim in broad daylight outside a busy supermarket.
“Approaching him from behind, Clarkson suddenly slashed the victim’s throat several times with a knife, leaving a number of gaping wounds, the largest of which was 10cm long. The wounds missed the carotid artery by only five mm.
“It is clear that it is only by great good fortune that this crime was not still more serious. The victim was very lucky to escape with his life. Clarkson will now be serving a considerable length of time in prison, and I hope this is of some comfort to his victim.”