A retired British Army colonel, famous for his inspirational speech on the eve of battle in Iraq, says the Duke of Sussex has "now turned against the other family, the military".
In his new tell-all memoir, Prince Harry has disclosed that he killed 25 people in Afghanistan while serving as an Apache pilot in the British Army.
Responding to the claim, Colonel Tim Collins told Forces News: "This is not how we behave in the Army; it's not how we think."
Col Collins completed three tours with the SAS and UK Special Forces.
His rousing speech to British troops on the eve of the Iraq War in March 2003 made headlines worldwide and a copy of it was mounted in the Oval Office in the White House.
'He has badly let the side down. We don't do notches on the rifle butt. We never did.'
The colonel has accused the Duke – who alongside the Duchess of Sussex stepped down as a senior Royal in 2020 – of pursuing "riches he does not need" and rejecting "family and comradely love that he badly needs".
He told Forces News: "Leonardo Da Vinci once said: 'He who wishes to be rich in a day will be hanged in a year'.
"Prince Harry's latest revelations in his memoir 'Spare' are clearly a tragic money-making scam to fund the lifestyle he can't afford and someone else has chosen.
"Amongst his assertions is a claim that he killed 25 people in Afghanistan. That's not how you behave in the Army; it's not how we think. He has badly let the side down. We don't do notches on the rifle butt. We never did.
"The British Army was deployed to Afghanistan to assist the lawful government and the benighted people – not to kill them. We lost people dead and insurgents also died – as did some innocents caught in the conflict. But that was a regrettable consequence of a lawful intervention with the best intentions.
"Harry has now turned against the other family, the military, that once embraced him having trashed his birth family.
"He has chosen a path that is alien to us in the UK and the Commonwealth, pursuing US identity politics and casting slurs or racism around where none exists in any manner comparable to the USA.
"I wonder whose path he has chosen? In the end, I see only disappointment and misery in his pursuit of riches he does not need and his rejection of family and comradely love that he badly needs.
"He would be well to reflect that money does not actually exist. Ask anybody who invested in Bitcoin. However, love is real."
Prince Harry served in the Army for 10 years, undertaking two tours of Afghanistan and rising to the rank of captain.
His autobiography is due for publication on 10 January but accidentally went on sale in Spain under the title of En La Sombra, which translates as "in the shadow".
In the book he says he did not think of the 25 he killed as "people" but instead as "chess pieces" that had been taken off the board.
The book comes within weeks of Harry and Meghan's controversial Netflix documentary – in which he revealed that spending 10 years in the British Army helped "burst" the bubble he grew up in.
Prince Harry left the Army in 2015 but continued to have close ties with the forces, notably by founding the Invictus Games – the competition for injured, sick and wounded Armed Forces personnel and veterans which he established in 2014.