Explosive scenes have erupted outside a court after two teen thugs were jailed for fatally stabbing a 15-year-old as he tried to defend his mate in a robbery.

In a cruel twist, Angus Beaumont’s killers were ordered to serve 60 per cent of their sentences after the judgment was handed down at Brisbane Supreme Court on Tuesday.

Angus’ grieving parents voiced their outrage at the lack of remorse shown by their son’s killers as security guards attempted to keep both families separated in and out of court.

It culminated with Ben Beaumont, Angus’ father, clashing with a family member of one of his son’s killers.

“F**king scum,” Beaumont said to the man as he challenged him to a fight.

Angus was fatally stabbed through the heart on a street in Redcliffe, north of Brisbane, on March 13, 2020.

The boys involved were both only 14 at the time of the murder.

They are now 16 and 17 but because they were juveniles at the time of the offence, they cannot be identified under Queensland law.

The 16-year-old Kiwi received nine years’ detention, while the 17-year-old received seven and a half years’ detention.

However, they were both ordered to serve only 60 per cent of their respective terms.

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Their time in pre-sentence custody - 720 days for 16-year-old and 776 days for the 17-year-old - was also declared as time served.

A supporter of one of the boys said “I love you” as he was led away to the cells following the sentence.

Michelle Liddle and Ben Beaumont, the mother and father of slain teenager Angus Beaumont, voiced their outrage at the lack of remorse shown by their son’s killers. Photo / Sarah Marshall, NCA NewsWire

Outside court, Angus’ family said they had faced “intimidation” from the two boys’ families, even leading up to the sentence.

“We’re penalised, my son was penalised … for not being a criminal,” Angus’ mum Michelle Liddle told reporters.

“There is no remorse.

“These people have mocked us, they have laughed about our son’s death.

“The killers have made up little rap (songs) about his death, they do not care.”

Liddle said a family member of the boys had “laughed” about “how stupid” her son was to take the pair on.

She said she felt the courts were being “played” by the boys.

“It’s got to change … the youth justice system has to change,” Liddle said.

“This is just so wrong.”

A jury found both the boys guilty of murder earlier this year.

Justice David Jackson said the boys had arranged to buy marijuana from Angus’ friend for A$25 but demanded more, brandishing a knife.

The court was told they believed they had been “ripped off” purchasing the drugs – something Justice Jackson rejected as the evidence did not explain how they came to this conclusion.

“This is minimisation of your responsibility,” he said.

Angus’ group of friends fled in different directions but Angus and his friend ended up in a confrontation with the boys.

Justice Jackson said the fight only lasted a matter of seconds.

Angus, who had armed himself with knuckle dusters and was handed another knife, was stabbed by one of the boys as they both approached him from different sides.

Justice Jackson said the pair “touched hands” as they left, calling it a gesture of “having won the fight”.

One of the boys was also convicted of vehicle offences committed while he was on bail for Angus’ murder.

The court was told he stole a car, driving on the wrong side of the road before police surrounded the car.

Justice Jackson said both boys had an extensive criminal history involving violence and vandalism.

Both boys had experienced violence and hardship growing up, including exposure to substance abuse and homelessness, Justice Jackson said.

He took into account their remorse they had demonstrated while in custody and the harsh lockdown periods in jail.

- Blake Antrobus, news.com.au