As the situation escalated, the woman’s boyfriend in the UK contacted the Chinese Consulate in London, who opened a case file and confirmed they could help.
However, a “blackout” in communication occurred because the British Consulate in Shanghai had not yet opened for the day.
“I couldn’t get through to anybody, my parents, my boyfriend, and even the London consulate couldn’t get through to anybody in China,” she explained.
She told the BBC said she was eventually escorted through security and onto a plane back to the UK.
She said it was a stressful experience and it “almost felt like a little bit like a fugitive.
“It felt like I’d done something really wrong, and I felt really stupid.”
Her passport was confiscated for the duration of the 12-hour flight and only returned to her once she landed back at Gatwick.
“Nothing makes you feel quite more alone than being refused entry to a country and then not sure what’s happening with yourself,” she said.
While the woman has now returned safely to the island, she has written to the Cabinet Office to seek clarity on why the Manx passport, which identifies the holder as a British Citizen, was not recognised under the international agreement.
“I don’t blame the people at immigration for questioning it… but also to know that some formal agreement has been signed and half of the people I know in London and England agree that I’m supposed to be in there but the people in China don’t.”
The BBC has contacted the Isle of Man Government for comment.