Travellers who arrive in the UK from 22 "red list" countries will be forced to quarantine in government provided accommodation for ten days.
Prime Minister Boris Johnson announced new border restrictions for travellers arriving in the UK from certain countries.
The Prime Minister announced the measures in the House of Commons this afternoon.
Mr Johnson told the Commons: "I want to make clear that under the stay at home regulations, it is illegal to leave home to travel abroad for leisure purposes.
"We will enforce this at ports and airports by asking people why they are leaving and instructing them to return home if they do not have a valid reason to travel.
"We have also banned all travel from 22 countries where there is a risk of known variants including South Africa, Portugal and South American nations.
"And in order to reduce the risk posed by UK nationals and residents returning home from these countries, I can announce that we will require all such arrivals who cannot be refused entry to isolate in Government provided accommodation, such as hotels, for 10 days without exception.
"They will be met at the airport and transported directly into quarantine. The Department of Health and Social Care is working to establish these facilities as quickly as possible."
Home Secretary Priti Patel added more detail to what the measures would entail as she addressed MPs in Parliament.
Ms Patel said: "Police have stepped up checks at addresses to ensure people are self isolating.
"We will refuse entry to people coming from red list countries and UK nationals and residents returning from these countries will be placed into managed isolation and required to isolate for ten days without exception.
"Despite the rules to stay at home we are still seeing people not complying, people should be staying at home unless they have a valid reason to leave and a holiday is not a valid reason.
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"So now people must make a declaration about why they want to travel and carriers will be checking these reasons.
"We will increase police presence at ports and airports and officers will ask people for their reasons for travel.
"We will also review the travel exemptions list, for people who are allowed to travel.
"If you don't follow the regulations you will face a fine."
