The US president made his comments in an interview with Fox News in which he reiterated his suggestion that Nato would not support America if asked.

He said: “We’ve never needed them.

“They’ll say they sent some troops to Afghanistan… and they did, they stayed a little back, a little off the front lines.”

His remarks drew condemnation from across the political spectrum, with critics pointing to the 457 British deaths in Afghanistan and highlighting Mr Trump’s avoidance of military service in Vietnam.

The only time Nato’s mutual defence arrangement has been invoked was after the September 11 terrorist attack on the US in 2001, when allies aided American forces in response to the atrocities by al-Qaida.

Paratrooper Mr Parkinson, from Doncaster, is widely viewed as the most severely injured British soldier to have survived the war.

The blast left the former lance bombardier in 7 Para RHA with both legs amputated, a twisted spine and brain damage.

Mrs Dernie said: “I can assure you, the Taliban didn’t plant IEDs (improvised explosive devices) miles and miles back from the front line.”

She said Sir Keir has “got to stand up for his own armed forces, and he’s got to absolutely refute what Donald Trump said”.

“Call him out,” she said.

“Make a stand for those who fought for this country and for our flag, because it’s just beyond belief.

“Come and look at us, the life that Ben leads – 19-and-a-half years on, still fighting for his care, still fighting for him to have a decent life, recovering from a recent operation.

“To hear this man say: ‘Oh, well, you just fannied about behind the front lines’… It’s the ultimate insult.”

Ian Sadler, whose son, Trooper Jack Sadler, 21, was killed in Afghanistan in 2007, while serving with the 4/73 Special Observation Battery, Brigade Reconnaissance Force, said: “Trump is just ill advised by his military aides and the people around him.

“Some of the Nato troops were not on the front line in the same way the British and US troops were, that’s true.”

But Mr Sadler, from Exeter, Devon, added: “The British certainly were in the hot spots, they were on the front line, 457 of them were lost and there was probably three times as many seriously injured as deaths.”

Sir Keir will speak to Mr Trump about his “deeply disappointing” claims that Nato troops stayed away from the front line, a minister said.

Care minister Stephen Kinnock said there was no basis for the president’s claims.

“President Trump’s comments are deeply disappointing, there is no other way to say that,” he told Sky News.

“I don’t know really why he said them.”

Asked whether the US president should apologise, he told LBC: “Our Prime Minister does things his way. He works behind the scenes, effectively building alliances, building coalitions.

“I think he will, I’m sure, be raising this issue with the president.”

The row further tests the transatlantic relationship, which has come under intense strain following Mr Trump’s threats to slap tariffs on European nations opposed to his ambitions to annex Greenland.

He later backed down after a meeting with Nato secretary-general in which he said they formed the “framework” for a deal over Arctic security, announcing further import taxes would no longer be imposed.

Calvin Bailey, a Labour MP and former RAF officer who served alongside US special operations units in Afghanistan, told the Press Association Mr Trump’s claim “bears no resemblance to the reality experienced by those of us who served there”.

Conservative MP Ben Obese-Jecty, who served in Afghanistan as a captain in the Royal Yorkshire Regiment, said it was “sad to see our nation’s sacrifice, and that of our Nato partners, held so cheaply by the president of the United States”.

Tan Dhesi, chairman of the Commons Defence Committee, said the president’s comments were “appalling and an insult to our brave British servicemen and women, who risked life and limb to help our allies, with many making the ultimate sacrifice”.

Foreign Affairs Committee chairwoman Dame Emily Thornberry described them as “so much more than a mistake”, and “an insult” to the families of those who had died.

The UK suffered the second highest number of military deaths – 457 – in the Afghanistan conflict, behind the US, which saw 2,461 deaths.

In total, America’s allies suffered 1,160 deaths in the conflict, around a third of the total coalition deaths.

Mr Trump has previously been criticised for avoiding being conscripted to fight in Vietnam thanks to being diagnosed with bone spurs in his heels – a claim that has been subject to significant doubt.

Former Scottish soldier, author and journalist Stephen Stewart said: “It’s hugely ironic that someone who allegedly dodged the draft for the Vietnam War should make such a disgraceful statement.

“He has desecrated the memory of hundreds of British soldiers who made the ultimate sacrifice in Afghanistan, people who we called friends and comrades.”

Liberal Democrat leader Sir Ed Davey said in a post on X: “Trump avoided military service 5 times.

“How dare he question their sacrifice. Farage and all the others still fawning over Trump should be ashamed.”