A knifeman left his victim millimetres from death when he slashed his throat in a shocking street attack.
Gavin Hanratty was unhappy that his ex partner had started a relationship with a new man, who he disapproved of, was spending time with his children.
Newcastle Crown Court heard the simmering situation came to a violent climax in the early morning of June 28 when the furious 33-year-old turned up at his ex's home to confront him.
In the violence that followed, which involved the victim arming himself with a hammer, Hanratty used a craft knife to slash Mr Baker's neck, leaving a ten centimeter wound.
Prosecutor Mark Giuliani told the court if the injury had been "literally a few millimetres deeper", his victim's carotid artery and jugular vein would be
cut - resulting in certain death.
Hanratty, of Vine Street, Sunderland, was initially accused of attempted murder but the charge was dropped when he pleaded guilty to wounding with intent and having an offensive weapon.
He was jailed for eight years.
Mr Justice Jay said: "You have got a few millimetres and this is absolutely grievous bodily harm with intent, dead body, murder, 25 years minimum.
"You are millimeters away from that.
"The differences are millimetric but the consequences are massive."
The judge said the victim has been left with a permanent, "unsightly" scar on his neck and has said in his victim statement he has been badly effected by what happened to him, resulting in a loss of confidence and fear of going out.
The court heard the night before the confrontation, Hanratty had texted his ex-partner and warned "If I've got a blade I will use it" and "i'm about to go
Prosecutor Mark Giuliani told the court Hanratty had been unhappy about his ex's choice of new partner, who had been spending time with his children,
because he believed Mr Baker to be a drug user.
Mr Giuliani said: "His basis of plea is for some time prior to the attack, the defendant had been concerned about his ex-partner's relationship with the
"It is clear the defendant had been told the complainant in this matter was a drug user.
"Whether it is true or not, the crown accept he had a genuine belief in that."
The court heard the victim had brought a hammer out of the house as Hanratty was starting to walk away after shouting and screaming for him to come out.
Hanratty then brought the blade out of his pocket and slashed his victim's neck, once.
The court heard the wound was treated at hospital with staples and Mr Baker discharged himself, against medical advice, later that day.
The weapon Hanratty used in the attack has never been found.
The court heard Hanratty is a former user, who has awareness of the "devastating" impact drugs can have on families and did not want his
John Wilkinson, defending, said it was not a sustained or planned assault and consisted of just one blow.
Mr Wilkinson said: "This was not a case of a knfie being taken there deliberately to cause harm.
"There was an element of excessive self defence, if he's being attacked by a man with a hammer."