One of Britain’s most wanted fugitives who evaded justice for three and a half years has been jailed for life.

Shane O’Brien, 31, slashed the neck of 21-year-old Josh Hanson in an act of “pitiless savagery” at a west London bar in October 2015 before fleeing the UK in a private plane.

He used false travel documents to evade police until he was arrested in Romania and brought back to Britain in April.

He was found guilty of Hanson’s murder after an Old Bailey jury deliberated for 55 minutes.

Hanson’s mother, Tracey, and sister, Brooke, read out victim impact statements as the defendant awaited sentencing on Wednesday.

Tracey Hanson tearfully described her son as a “considerate, kind and generous” man who was a “rising star” in his work. She told the court: “On 11 October 2015 my life changed for ever.”

She received a call to say he had been stabbed in the early hours and was 10 minutes away when he died. She told the court: “He was taken from us in the most horrific way possible: suddenly, abruptly, viciously and violently.” She added that she had been unable to grieve for him without justice.

Josh Hanson, 21. Photograph: Metropolitan police/PA

Brooke Hanson said: “Josh was not just my brother, he was my best friend.” His smile was “infectious” and his presence “magical”, she added.

She told the court she now had anxiety and post-traumatic stress disorder and often wondered whether she could have protected him from the “evil” that took him away.

His grandmother, Mary Hanson, said in a statement read on her behalf that at the age of 80, she did not want to carry on when her grandson died. She wrote: “There is not a day when I don’t think about my grandson. I cry for him every day, what he went through and how he suffered.”

The judge, Nigel Lickley QC, jailed O’Brien for life with a minimum term of 26 years.

He 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 Hanson with a blade, O’Brien “calmly” walked away, leaving him to die in front of “shocked and traumatised” friends, the judge said.

There were angry shouts of “coward” from the public gallery as O’Brien was led from the dock.

During his Old Bailey trial, jurors were shown CCTV footage of the attack on Hanson, a roads planner, in the early hours of 11 October 2015.

Hanson could be seen clutching his throat and stumbling after sustaining a 37cm (14.5in) wound from his left ear to the right side of his chest.

After calmly leaving the bar, O’Brien asked a friend to secure a chartered four-seat plane to take him from London Biggin Hill airport to the Netherlands, the court heard.

O’Brien grew long hair and a beard and got a tattoo of his daughter’s name covered over as he used false identity documents to travel to countries including Germany, Belgium and the Czech Republic.

Friends helped him lay low after he was added to Europol and Interpol’s most wanted lists, his trial heard.

Despite being arrested in Prague in 2017 for assault, he slipped through the net after using an alias and fled when released on bail.

O’Brien denied murder, claiming he felt threatened by Hanson’s “very aggressive body language”.

He told jurors he only wanted to scare Hanson and did not mean for the blade to make contact.

The court heard O’Brien had two previous convictions for having a blade and had shown no remorse.