Meghan Markle could be left without British citizenship after she and Harry announced they are to split their time between North America and the UK.
The Duchess has to follow one rule if she wants to become a British citizen – she cannot live out of the country for more than 90 days.
Meghan is thought to be in the second year of the five-year process towards naturalisation after her wedding in May 2018.
But the Sussexes’ move to Canada will take Meghan away from the ‘strong commitment to the UK and an intention to live here’, a government source said.
Meghan must not have left the UK for more than 270 days in the three years before applying for it.
This can be spread over the three years but must include 90 days in the last year.
Harry must also meet a minimum income threshold of £18,600 a year, or have cash savings above £16,000.
Meghan would need to take a test with questions on life in the UK, which costs £50.
Michael Marziano, senior immigration lawyer at Westkin Associates, told Sun Online that the US citizen has to be living in the UK with the British partner when the application is made.
He said: “They must intend to continue to live together permanently in the UK.
“If there has been any period throughout the first 2½ years where they have not lived together in the UK, government guidance states there must be good reason for this.
“It must be consistent with their continued intention to live in the UK permanently.”
Harry and Meghan announced that they are stepping back from their senior positions in the royal family while Megan is said to want to become more involved in politics.
She will now be much more free to express herself publicly after the couple declared they would become financially independent.