Prince Harry and Meghan Markle's trip to the Netherlands for the Invictus Games has put the issue of royal security back in the spotlight.
Harry is currently locked in a legal battle with the UK government over a decision to downgrade his security.
He is bringing a claim against the Home Office after being told he would no longer be given the same degree of personal police protective security when visiting from the US, despite offering to pay for it himself.
The duke says he wants to bring his children to visit, but he and his family are “unable to return to his home” because it is too dangerous, his legal representative has said.
Although it has emerged he and Meghan have travelled to the UK for secret meetings with both the Queen and Prince Charles yesterday - and today are in The Hague for the Invictus Games.
It's unclear what this will mean for Harry's legal battle as the issue of royal security can be complex.
And according to a former royal protection officer, it is often an emotive subject, especially for high-profile individuals such as members of the royal family.
Security expert Simon Morgan worked as a royal personal protection officer from 2007 to 2013, looking after the likes of the Queen, Prince Charles and even Harry.
And he told the Mirror that security is often a sensitive issue for high-level individuals, who have to be able to trust the people employed to look after them.
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He said: "Security at that level is very much built up on rapport and trust - your role is to allow them to lead their lives and preserve life.
"People like members of the royal family often have security from the cradle to the grave and have close protection that stays with them.
"It's a very emotive issue, I can see both sides of the argument with Prince Harry. He has grown up always having police protection.
"He would have come to value his protection team and would have seen its value.
"But from a UK perspective, there is a duty of care - and if there was a threat that became that great they would deliver some form of protection as they would for me or you."
If Harry, a former Afghanistan veteran, does not win his legal battle to have police protection in the UK, he will instead have to employ private security guards.
Mr Morgan himself is the director of operations at a private London-based security consultancy team Trojan Consultancy, where the team are made up of former police protection officers.
He explained that to become a royal police protection officer you must have 10 to 15 years of experience with the Metropolitan Police before you can apply for the role, which has a six-month training period and ongoing training.
In contrast, obtaining a close security licence through the Security Industry Authority can be done with just a two-week training course.
Private security is also not allowed to carry firearms in the UK and according to Mr Morgan may find it more difficult to access intelligence or even have to pay for it in some countries.
When Harry and Meghan are in the Netherlands, it has been reported that their private security team have liaised with Dutch authorities and secured a “high-level multi-agency protection programme” for the couple for the duration of their trip.
Sources have confirmed reports that the Dutch national police’s DKDB Royal and Diplomatic Security Service will have overall responsibility for the Sussexes.
Mr Morgan says when protecting the royals and other high-profile people, working with multiple agencies was a normal part of the job and there was a lot of preparation and contingency planning depending on what happened at the events royals were at.
He says you're always thinking "what if, what if" and constantly thinking of contingency plans.
Mr Morgan explained: "You have to get it right every time - the bad person only has to be right just once.
"You often look like a graceful swan skimming the surface but your feet are going 10 to the dozen under the water."
But despite getting to work alongside the royals and often travelling to glamorous places, he added most days as a royal protection officer would be filled with meetings about contingency plans or visiting hospitals.
He said: "“In reality it’s certainly nothing the the TV show The Bodyguard.”
