The list of "safe ways to travel" in the UK was reduced to just nine countries – including Gibraltar, San Marino and Liechtenstein – after more destinations were flagged.
Arrivals from Denmark, Iceland, Slovakia and the Caribbean island of Curacao were restricted this weekend.
Travelers returning to England from these destinations must be quarantined for 14 days after their return.
Transport Minister Grant Shapps announced tonight that Denmark is one of four countries to be placed on the government's "red list" of travel quarantine.
The new rules go into effect on Saturday morning at 4 a.m. and mean that Brits can travel to just seven countries without restrictions at either border.
THE NINE NATIONS IN UK & # 39; S GO FLY ZONE
Germany, Poland, Italy, Sweden, Turkey, Greece, Gibraltar, Liechtenstein and San Marino are the only countries the British can travel to without facing quarantine or bi-directional testing.
Mr Shapps also said no countries will be removed from the "red list" this week.
Other countries on the UK's "green list" – including Singapore, Thailand, Vietnam, Finland and the Seychelles – are either closed to travelers, require a quarantine of up to 14 days or only allow travelers with a negative Covid test in the last 72 days Hours.
The decentralized administrations often update their own lists after the UK government announces its weekly changes for England.
In the past two months, the government has dramatically hacked its list of "green" countries – Spain, France, Croatia, Slovenia, Hungary, Belgium, Austria, Switzerland, Malta, the Netherlands, the Czech Republic and mainland Portugal.
Mr Shapps reminded travelers that they are required by law to fill out a "Passenger Location Form" on their return to England.
Announcing the changes, Mr Shapps tweeted: “Data shows we need to remove DENMARK, SLOVAKIA, ICELAND and CURACAO from the list of travel corridors.
Transport Minister Grant Shapps announced today that Denmark, Slovakia, Iceland and Curacao will be placed on the government's red list of travel quarantine.
“If you come to the UK from these destinations after 4am this Saturday, you will have to self-isolate for 14 days.
& # 39; We won't be adding any destinations to the list of travel corridors this week.
& # 39; Remember, if you are entering the UK you MUST be legally required to complete a passenger search form.
"This protects public health and ensures that those who have to do so comply with the rules of self-isolation."
The UK government currently uses a threshold of 20 cases per 100,000 when deciding whether to add or remove countries from its quarantine list.
Downing Street remains under heavy pressure to change UK quarantine rules amid mounting fears for the future of the aviation and travel industries.
Ministers have been urged for months to replace the current 14-day self-isolation restrictions on people returning to the UK from high-risk countries with a more sophisticated system of airport tests.
Proponents believe tests on arrival could open the door to cut the two-week quarantine period to potentially less than seven days.
A dual testing approach would test travelers upon arrival and then ask to self-isolate for about five days when tested a second time.
Two negative tests would be enough to allow people to end their quarantine period and return to normal life.
Ministers were reluctant to approve airport tests, however, amid concerns that the approach might fail to identify some people with the virus.
This is due to the time it can take for the virus to be detectable after the time of infection.
However, many MPs believe that the current blanket approach to quarantining travel cannot last long due to the damage it is doing to the aviation sector.