Immigration powers have been imposed against foreign visitors, denying all who have been in Denmark in the past 14 days entry into the UK.
The rule came into force as of 4am on Saturday.
The government also announced it is expanding the self-isolation requirements for Denmark, after the country was removed from the government’s list of travel corridors on Friday.
British nationals or residents who are returning to the UK either directly or indirectly from the country are now required to self-isolate along with all other members of their household, until two weeks have passed since they were last there.
A spokeswoman from the Department for Transport said in a statement: “Unlike other travel to the UK, there will be no exemptions to this quarantine policy.
“Anyone who has returned from Denmark within the last two weeks will be contacted to ensure they complete the self-isolation needed to ensure the virus does not spread across the UK.
“The UK government is working closely with international partners to understand the changes in the virus that have been reported in Denmark and we are conducting a programme of further research here in the UK to inform our risk assessments.”
The travel ban and extra requirements will be reviewed after a week, the department added.
“Decisions on border measures and travel advice can be changed rapidly if necessary to help stop the spread of the disease and further announcements regarding freight will be made later today,” the spokeswoman said.
Denmark was also added to Scotland’s travel quarantine list, with Nicola Sturgeon announcing the move at the Scottish government’s coronavirus briefing on Friday, minutes before it came into effect at 12.30pm.
The Danish government said a mutation of the coronavirus had been found in 12 people infected by minks, which farmers have been ordered to cull en masse, but experts said the significance of any variant strain and its effect on humans was unclear as it is yet to be studied.
Denmark is the world’s largest mink fur exporter and produces an estimated 17 million furs per year.
The Danish government has ordered the cull of all 15m minks bred in the country’s 1,139 mink farms.