Tracey Hanson described her living “nightmare” after her son’s killer was finally brought to justice, after three-and-a-half years on the run.
Shane O'Brien became one of Britain's most wanted fugitives after he slashed the neck of 21-year-old Josh Hanson in a bar in Hillingdon.
He was given a life sentence today, and will serve a minimum of 26 years.
Police launched an international manhunt but O'Brien, 31, continued to evade police until he was arrested in Romania and brought back to Britain in April.
Speaking outside court, Tracey said: "This is a mother's worst nightmare and one I will never wake up from.
"My son was taken from me in the cruellest way possible. I will never hold him again. Nothing could ever be said in a courtroom to address that but today's sentence goes some way to giving us the space we need to start to breathe."
During O'Brien's Old Bailey trial, jurors were shown graphic CCTV footage of the attack on roads planner Mr Hanson in the early hours of October 11 2015.
The jury took just 55 minutes to find O'Brien guilty of murder.
Sentencing, Judge Nigel Lickley QC said: "This was a grotesque, violent and totally unnecessary attack on an innocent man.
"The reason why you behaved in such a way may never be fully explained. You, however, know the reason."
Having slashed Mr Hanson with a blade, O'Brien "calmly" walked away, leaving his victim to drown in his own blood in front of "shocked and traumatised" friends, the judge said.
Later, Tracey continued: "I can never move on. I can only move forwards. Josh's memory will live on, not only in our hearts but through the Josh Hanson Trust, the charity we set up in his name.
"If we can save one life, keep one son by his mother's side, ensure one person gets home safely when they otherwise wouldn't have, then we will have made the world a more bearable place.
Earlier in a victim impact statement read to the court, Ms Hanson had tearfully described her son as "considerate, kind and generous".
She told the court: "On the 11th October 2015 my life changed forever."
"He was taken from us in the most horrific way possible - suddenly, abruptly, viciously and violently."
His sister Brooke said: "I just want to say thank you to everyone that has done everything for Josh the last four years. If it stops another innocent young man from being killed on the streets then something good has come out of today."
Detective Chief Inspector Noel McHugh, of Scotland Yard, described O'Brien as a "wicked individual" and "a knife carrier who clearly does not think twice about using it".
Reacting to the sentence, he said: "I am pleased for Josh's family. I'm pleased that Shane O'Brien is going be in prison for 26 years, a significant amount of time he is going to be away, and quite rightly so when you look at the barbaric attack he carried out on Josh in that bar.
"He stood no chance. Within five seconds of Shane O'Brien's actions, Josh paid with his life."
"Here we had video of Josh being murdered and dying and it's horrendous to look at.
"Although it takes five seconds, it feels like it is in slow motion. It's incomprehensible to see someone die in front of you. Difficult for us as police officers but one can only try and imagine what that's like for a family."
The officer said the family had asked for "brutal" CCTV footage of the attack to be released to bring home the reality of knife crime.
He said: "What Tracey and Brooke and all the other families who end up being at the Old Bailey through other people's actions are trying to get the across is it is real. You are ruining families, ruining communities, you are ruining your own life."
"If you look at that pain, will it stop people from carrying weapons? We already know from Tracey's work with charity some young people say they have been encouraged and supported from not being engaged in that knife crime activity."
The court heard that O'Brien had two previous convictions for having a blade and had shown no remorse.
There were angry shouts of "coward" from the public gallery as O'Brien was led from the dock.
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