Ban comes amid rising tensions between the UK and China over semi-autonomous Hong Kong, a former British colony.
Hong Kong banned all passenger flights from the UK from Thursday because it seeks to curb the spread of new variants of the coronavirus.
In a statement from the Hong Kong government on Monday, the UK was rated as “extremely high risk” due to the “recent recovery from the epidemic situation in the UK and the widespread strain of the virus Delta variant here “.
Under the classification, people who have been in the UK for more than two hours will be limited to boarding passenger flights in Hong Kong.
The city confirmed its first local COVID case involving the Delta variant last week, ending a 16-day streak of zero local cases.
This is the second time that the Hong Kong government has banned flights from the UK, following a restriction imposed last December.
The ban comes amid rising tensions between the UK and China over semi-autonomous Hong Kong, which was a British colony until it was relegated to China in 1997.
The UK has criticized China for imposing a national security law on Hong Kong and tightening control of its media, saying Beijing was undermining the city’s autonomy.
The flight ban was triggered by a policy put in place by the government to prevent the spread of coronavirus variants in Hong Kong.
A suspension of passenger flights is imposed if five or more passengers arriving from one place test positive on arrival for a particular variant of coronavirus, or a relevant virus mutation within a period of seven days.
A ban is also issued if 10 or more passengers from one location are confirmed to be infected with the coronavirus through any test, including tests performed during quarantine, over a seven-day period.
The UK reported 14,876 people tested positive for coronavirus on Sunday, as it saw a recent rise in infections. It has confirmed more than four million cases since the pandemic began.
Hong Kong, which for months has imposed a 21-day quarantine on arrivals from most countries and implemented strict social exclusion rules, reported three new cases of coronavirus on Monday. It has confirmed a total of 11,921 cases since the pandemic began.
The ban on flights to the UK comes as Hong Kong seeks to relax quarantine measures for most other countries, including the United States and Canada.
But several other countries, including the Philippines, Nepal, India, Pakistan and Indonesia, are also banning flights to Hong Kong.