Ken Wharfe, who was a royal protection officer to Harry, Prince William and their mother, Diana, Princess of Wales, believes the duke has "played the wrong card" regarding his security.
Harry can't expect the "all-singing-and-dancing protection" he had in the United Kingdom" when he was a working member of the royal family, like his father, King Charles and his brother, the Prince of Wales, Wharfe said.
Harry now needs to show some "humility" if he wants to begin talks with his UK family, along with the government and police, to try and improve his security.
Harry has called for the Home Secretary to review the body that authorises protection for senior royals after he lost a Court of Appeal challenge last week over his security arrangements while in the UK.
He told the BBC he "can't see a world in which I would be bringing my wife and children back to the UK".
But Wharfe says Harry "has really played the wrong card".
"I don't see how he can expect to get full protection when he arrived back in the UK, when he is no longer a member working the royal family, when he knows that the actual security package comes at the expense of the British taxpayer," he told the PA news agency.
"The High Court has seen that. The appeal court has seen it. The government has seen it. The police have seen it - so where's the problem?"
Harry failed in his appeal against the dismissal of his High Court claim against the Home Office, over the decision of the Executive Committee for the Protection of Royalty and Public Figures that he should receive a different degree of protection when in the UK.
He told the BBC he can only come to the UK safely if he is invited, and King Charles could help resolve the situation by "stepping aside and allowing the experts to do what is necessary".
"I have had it described to me ... that this is a good old-fashioned establishment stitch-up, and that is what it feels like."
Harry says the decision "is knowingly putting me and my family in harm's way". Wharfe said: "With regards to the stitch-up, I think that's really offensive ... I think what he should be doing now is actually showing some humility, certainly towards his father.
"If a reconciliation is part of what he wants, then this is hardly the way to go about reconciling the differences that exist within your family."
Harry's level of security changed in 2020 when he and his wife Meghan stepped down as working royals and moved to Canada, and then California.
