Henry Nowak died after the knife attack in the southern England city of Southampton last December.

His killer Vickrum Digwa, a 23-year-old Sikh man, was sentenced to life in prison on Monday, having lied to police at the time that ​Nowak had assaulted him.

In police bodycam footage, Nowak is seen lying on the street saying “I’ve been stabbed” and “I can’t breathe” while an ​officer responds “I don’t think you have, mate”.

Prime Minister Keir Starmer said there were “serious questions” to answer, including how “allegations of racism ⁠informed or fed into the decision-making in that particular case.”

“It is impossible to watch that footage and not appreciate that those questions absolutely have ​to be answered,” Starmer told reporters.

Judge William Mousley acknowledged in court on Monday that the case had stirred racial tension across Britain.

Nigel Farage, whose anti-immigration Reform ​party leads opinion polls, said it was an example of the rights of ethnic minorities trumping those of white British people.

“We should respond to this with pure cold rage.”

‘Inhumane and degrading treatment’

A protest later on Tuesday outside the Southampton ​police station drew a few hundred people chanting “I can’t breathe”, including anti-immigration activist Tommy Robinson.

Other protests have been advertised for this week.

Digwa stabbed Nowak with a knife ​he said he was permitted to carry due to exemptions for Sikhs to have ceremonial daggers.

When the police arrived, Digwa said his turban had been knocked off and ‌he had ⁠an injury to his eye.

Nowak’s family called his treatment by police “inhumane and degrading” but in a statement outside court, his father said his death should not be “used to create further division, hatred or tension”.

That was echoed by Britain’s Interior Minister Shabana Mahmood, who told parliament on Tuesday that everyone was equal before the law and urged calm during the investigation.

“We must condemn those who seek personal political profit from tragedy,” she said, warning that threats against ​police and inflammatory commentary were worsening the ​situation.

She said public services should ⁠assess only the risk a person poses, not race or religion.

Referencing previous efforts to tackle racism in policing, Mahmood said, “Whatever changes are made, it is important that nobody over-corrects or course-corrects such that all of us as citizens ​are no longer equal before the law.”

Reform leader Farage sought to draw parallels with the 2020 killing of ​George Floyd in the ⁠US which sparked the Black Lives Matter movement.

Floyd had said “I can’t breathe” as a police officer kneeled on his neck for several minutes.

Nowak died shortly after being handcuffed by police. Once they realised he was injured, they uncuffed him and started CPR.

The police force, Hampshire Police, has apologised.

In a separate statement on ⁠Tuesday, the ​force said one of the officers involved in the arrest had resigned, while three others ​were being treated as witnesses in the investigation.

A spokesperson for the Attorney General’s Office said it had received multiple requests to consider raising Digwa’s 21-year minimum sentence, adding that law officers ​had 28 days from sentencing to make a decision on any changes.