David Lammy said he raised the issue during what he described as a “robust” phone call yesterday, after Mr Vance appeared to attribute the teenager’s death to a “mass invasion” of people into Europe.

Mr Nowak, an 18-year-old student, was handcuffed by police who ignored his pleas that he had been stabbed as he lay dying. His British-born killer, Vickrum Digwa, had claimed he was the victim of a racist attack.

Speaking as Keir Starmer’s deputy — and noting that he and Mr Vance maintain an unlikely friendship despite stark political differences — Mr Lammy said they clashed over the facts of the case.

Mr Lammy, who is also Justice Secretary, told Sky’s Sunday Morning with Trevor Phillips: “I spoke to the Vice President yesterday and I wanted to emphasise a number of things.

“The first is that our democratic process is working well. This young man has been convicted. There is an investigation into the police by the independent police complaints authority.

“There is an investigation into Hampshire Police by the inspectorate. The AG (Attorney General) is looking at the sentencing in relation to this. The national police chiefs are looking at the guidance in relation to this.”

He added: “The second thing was I disagree with him – this has got nothing to do with mass migration.

“This young man (Digwa) was a Brit. Let’s be… clear about that, and I said, ‘Look, Mr Vice President, you’re wrong about this’, and it’s also the case that actually murder is coming down in the United Kingdom.

“So, we had an agreeable conversation, but we disagree.”

Henry Nowak was handcuffed by police as he lay dying from stab wounds

Mr Lammy’s comments follow the latest intervention from the Trump administration on the case. On Friday, Mr Vance wrote: “Henry Nowak died the same way a civilisation dies: abandoned, handcuffed by authorities who neither trusted nor cared for him, and accused of hate crimes he did not commit.

“His murder is as tragic as it is enraging.

“He should still be alive today, and he would be if the last few generations of European elites had stood their ground against the politics of self-hatred and the mass invasion of migrants, many of whom despise the West and the people who love it.”

In the post on X, Mr Vance said the response to Mr Nowak’s death should be “righteous anger”. The message came after violent unrest in Southampton on Tuesday, close to where the teenager was killed.

Asked whether he had given Mr Vance a ticking-off, Mr Lammy said: “We had an agreeable conversation because we have got a relationship, but I wanted to make him clear that I disagree with some of the facts that he was asserting and to present the facts to him.”

He added: “I also urged him that it’s not helpful to tweet in this way, partly because of what the Nowak family have asked for, and reminded him about their desire not to make this an issue of division and hatred, but to make this an issue of common sense.”

Questioned on whether he believed the Vice President had been racist, Mr Lammy told the BBC’s Sunday With Laura Kuenssberg: “I reminded him that the family have called for calm, they don’t want division… and, two, I reminded him also of the online space and how toxic that can become. So, we had a robust conversation, a respectful conversation.

“We remain colleagues and friends, we’re able to do that, and he has strongly-held views.”

Mr Vance’s intervention followed remarks from the US State Department, which linked “two-tier policing” to Mr Nowak’s death — a claim Downing Street has firmly rejected.

Digwa was sentenced to life imprisonment with a minimum term of 21 years for stabbing Mr Nowak with a ceremonial knife with a 21cm blade, which he carried as part of his Sikh religion.

The Independent Office for Police Conduct is investigating Hampshire Police’s response in Mr Nowak’s case.

Mr Lammy also confirmed that the Attorney General is considering whether to refer the killer’s sentence to the Court of Appeal under the unduly lenient scheme.