Knifeman stabbed victim in 'brutal and sudden' Metro station attack
Paul Luke thrust a blade into Blake Longstaff's lower back during the chance encounter at Tyne Dock in the early afternoon of May 2.
The 26-year-old attacker, who was "using drugs daily", then fled the scene "at speed", discarded his distinctive coat and then went to a Post Office to check his account in a bid to set up a fake alibi.
The shocking stabbing attack was captured on CCTV, which has been played in court.
Newcastle Crown Court heard Luke had just a "minor grievance" with his victim and has now been told by a judge he currently poses a "high risk of serious harm to the public".
Luke, of Whitehall Street, South Shields, denies he was responsible for the shocking daylight attack but was found guilty of wounding with intent and having an offensive weapon after a trial.
In a victim statement Mr Longstaff said: "I am still shocked at being the victim of a stabbing for no reason.
"I am in a lot of pain. This is going to have a significant impact upon me.”
The court heard the knife wound "just" missed one of Mr Longstaff's kidney's, which could have been "catastrophic".
Judge Robert Adams told Luke: "You used a weapon you carried. It appears to have been a chance encounter but you reacted to seeing him by stabbing him.
"You appear to have had a minor grievance only, he didn't attack you.
"This was a brutal and sudden attack, stabbing someone in the lower back, just missing his kidney.
"Had it hit his kidney, it could have been catastrophic.
"It was a wholly unprovoked attack, carried out while armed.
"You obviously, currently, pose a high risk of serious harm to the public.
"This was a public place, a Metro station in broad daylight."
David Comb, defending, said Luke, who has a criminal record but has never been to prison before, had a "dislocated and disadvantaged" upbringing.
Mr Comb said Luke has completed vocational courses while in custody on remand, as well as mental health, substance misuse and addiction programmes.
Mr Comb said the period of imprisonment may, in due course, be an "advantage" to Luke.
He added: "This is a person young enough and willing to make some progress in future."