A security expert has said Prince Harry should be allowed to keep his UK police protection as he is 'a target for terrorists'.
The Duke of Sussex, 37, was stripped of his taxpayer-funded security after stepping down as a full time working royal in 2020.
He employs a privately-funded bodyguard team in the US, but he claims they do not have adequate jurisdiction abroad.
This week, the Prince has applied for a judicial review of a Home Office decision not to allow him to personally pay for police protection for himself and his family when they are in the UK.
Now Graham Yuill, an SAS-trained ex-soldier, has argued private security cannot adequately protect the Duke of Sussex as they are not allowed to carry guns.
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The 63-year-old, who served as a bodyguard to the commander of the British forces during the Troubles, said he was "alarmed" at the Home Office's decision to remove the Prince's protection.
Yuill fears the Duke of Sussex could be the target for terrorists, who he believes will be monitoring the situation.
"I was quite alarmed by the news to be honest, because terrorists listen to and pick up things like this," he said.
"People forget that groups like the IRA and al-Qaeda are still around.
"Harry could be a target for them, especially in Scotland where there is a lot of open space and a lot of dangerous circumstances."
UK restrictions forbid private security from being armed at all - even with non-lethal weapons such as tasers and pepper spray.
Yuill said: "The other problem we've got is that a lot of private security in the UK are people who have got a security industry authority license.
"It's a course they go on for a week that makes them a bodyguard. They are not primed or trained to handle an actual terrorist situation.
"They won't check for bombs under cars and won't know what to look for if a threat walks through the door.
"There are former special forces soldiers and excellent former royal protection officers available in private security firms, but they can't be armed.
"I know who these kinds of people are, but the biggest issue is they're not allowed to have a firearm - it's illegal.
"So people can have all the training you want, they can look smart and look intimidating, but there's nothing you can do if you're not armed.
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"If a sniper ranges in at 1,500 feet away, if they were to fire a shot there's no way you can react."
Yuill claimed police would likely "shadow" the Prince anyway with units available to deploy if there were a terror attack.
However, the time taken to deploy such units could still leave Prince Harry vulnerable, he added.
"One of the first things they ask you when you're learning to provide protection is whether you'd be willing to jump in front of a target to take a bullet for them," he said.
"The problem is, in reality even if that might save your principal's life. If you are in a situation where you have to do that you've failed already.
"Harry will be an easy target for motivated terrorists because his security won't be able to react."