Security experts say Prince Harry and Meghan Markle‘s potential part-time move to Canada could be costly for Canadian taxpayers.

The Duke and Duchess of Sussex shocked royal watchers, and seemingly the Royal Family, when they announced they would “step back” from senior royal duties to carve out a new role for themselves and become financially independent.

Along with the announcement came news of their intention to split their time between the U.K. and North America, prompting speculation that the family of three would be taking up residence in British Columbia, where they recently vacationed over the holidays.

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“I don’t believe they can refuse the government of Canada’s security,” Larry Busch, an ex-RCMP officer, told Reuters. Busch has directed security for world leaders, including U.S. presidents and the Royal Family, in the past.

According to Mike Zimet, whose New York security firm has protected the likes of Bernie Sanders and Alec Baldwin, the cost would run into the millions, not unlike the security for Prince Harry and Markle’s royal wedding in May 2018.

“If they want private protection, then a whole machine needs to be built around them,” he told Reuters.

At this point, it’s unknown just how much security would be required to protect the royal couple and their child, but it would be defined by a threat assessment, said Joe Balz, ex-RCMP officer and president of GloProSec Preventative Services.

“There’s always going to be the odd idiot who causes some type of problem,” Balz said. He added that they would be safer in Canada than in the U.S., where gun laws are much less strict.

While one of Prince Harry and Markle’s main motivations for stepping back is gaining financial independence, their security detail is still decided on by the British Home Office, and they’ve yet to release any further information on this.

The shocking news first came on Thursday when the couple took to Instagram. Sharing a photo from their engagement announcement in November 2017, they wrote: “We intend to step back as ‘senior’ members of the Royal Family and work to become financially independent, while continuing to fully support Her Majesty the Queen.”

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They added that they hope this “balance” will allow them to raise their son “with an appreciation for the royal tradition” while also “providing our family with the space to focus on the next chapter, including the launch of our new charitable entity.”

Markle has since returned to Canada via Vancouver International Airport and transferred to a flight to Victoria. A spokeswoman confirmed to Sky News that Markle is now back with baby Archie.

It was rumoured Archie was staying with Markle’s good friend Jessica Mulroney, but Sky News reported he was with a nanny.

ET Canada confirmed that Prince Harry is due to follow the duchess early next week.

— With files from Reuters