Levi Westhead, 18, stabbed Mark Webster 12 times in the chest and abdomen after showing up at the dad-of-two's home on Carsluith Avenue, Blackpool, and demanding to see his 16-year-old daughter.
The obsessed teenager had been in a rocky relationship with the girl for about 18 months, during which time he had bombarded her with abusive text messages and told her to kill herself.
On the evening of July 23 2021, he armed himself with a knife and tried to force his way into her house with the intention of threatening her. But Mr Webster, 50, refused to let him in.
Westhead made his way around to the back of the house, where he scuffled with Mr Webster on the patio and stabbed him multiple times.
He claimed he acted in self defence - but a jury saw through his lies and found h guilty on January 28.
At his sentencing at Preston Crown Court today, Mr Webster, known as Web, was praised as 'a true man and a true hero', who was trying to protect his daughter from an 'evil, controlling, harassing' boy.
Westhead, dressed in a red polo shirt, sighed and rolled his eyes as victim statements from Mr Webster's heartbroken wife Michelle, his daughter, and his 12-year-old son were read.
Mrs Webster said: "I knew Web when I was 15, and we started going out when we're were 16 - childhood sweethearts. He was my first and only love. Words cannot begun to describe how heartbroken and devastated I am. We did everything together. We doted on each other. He was the love of my life. We had been together 31 years. He was the most placid, funny, loving gentleman.
"That night my Web was taken away was a night I will never forget and one I will relive on a daily basis. Web tried to protect his family and that's what he did, and ultimately paid with his life.
"Levi has taken away our world in such a senseless way. Our hopes and dreams have been completely destroyed and despite my best efforts I cannot imagine any future without (Mark) in our lives. This has completely destroyed me, my family, and all our lives.
"Web was the rock of the family, the heart and soul, and he paid the ultimate price to protect his family. A true man and a true hero."
His daughter described Westhead as 'an evil, controlling, harassing boy', who had abused her during their 18 months together.
She said: "I'm not comfortable going out any more. Any little noise I hear, I'm frightened. If I see someone who looks like (Westhead), I freeze.
"I have terrible nightmares of Levi killing me and killing my dad, and its very upsetting. My mum struggles to even go out not. We stay in most of the time. I don't even like being there any more. I don't feel safe."
Mr Webster's son said: "I really miss my dad. I'm really upset and angry and I have suicidal thoughts.
"My dad didn't deserve this. He's a hero and he will not see me grow up and will not be here for memories to come. I miss just spending time with him. I love my dad."
In mitigation, Judge Simon Medland heard that Westhead was 'immature' for his age, and did not intend to kill Mr Webster when he went to the family's home that day.
Andrew Thomas, defending, said: "It's clear to see that cases like this are a tragedy, but this one truly is a tragedy for all concerned and families on both sides.
"He's not asking for forgiveness, but he's genuinely sorry for what he has done. He will be sorry for the rest of his life.
"Mark Webster was blameless. More than that, Mark Webster was a brave man who acted in order to protect his family from the attack that he perceived was about to take place.
"Mark was a good man and a good husband and a very loving father. We know that (his family) are heartbroken and that nothing that I can say, or anyone can do, can repair the damage of Westhead's offence."
Handing down a life sentence with a minimum of 17 years, Judge Medland said: "This was an appallingly sad event which should never have happened. Mark Webster’s murder has robbed his immediate family of their father figure, and principal breadwinner.
"He was a much-loved and very caring man for whom nothing seemed too much trouble. He was a hard-working and sensible man, ‘an extra special human being’ ‘a placid gentleman’ ‘loved by so many people’ ‘gentle’, ‘lovable’, ‘a true man’ and a ‘true hero’ who had established for his family a decent living and a decent way of life; he died protecting them.
"The loss suffered by Michelle Webster and her family is irreparable. The reality is that no sentence any court could ever impose could equal the value of Mark Webster’s life. To respectfully adopt Michelle Webster’s own phrase: ‘no sentence could ever be enough’. Therefore I do not endeavour oday to attempt that impossible feat; rather, I endeavour to impose a sentence which is proper in this particular case on these particular facts."