Transport Secretary Grant Shapps today announced Turkey and Poland are being added to the Government's travel quarantine 'red list' - but holidays to Greece and Italy are still allowed.
As of 4am on Saturday anyone returning from Turkey or Poland, as well as the Caribbean islands of Bonaire, St Eustatius and Saba, must quarantine for 14 days.
There had been speculation that restrictions were going to be imposed on Italy and Greece after a spike in cases but the two nations were ultimately given a reprieve.
Mr Shapps tweeted this evening: 'TRAVEL CORRIDOR UPDATE: The latest data indicates we need to remove Turkey, Poland, and Bonaire, St Eustatius and Saba from the #TravelCorridor list this week.
'This means if you arrive from these destinations from 4am Saturday 3 October, you will need to self-isolate.'
He added: 'You MUST self-isolate if you enter the UK from a non-exempt country - from tomorrow, we’re increasing the penalties for people who refuse to do so to a maximum of £10,000 for repeat offenders.'
There were fears earlier today that Greece and Italy could be subject to quarantine rules after the former recorded 20.5 cases per 100,000 people in recent days while Italy was at slightly above 20 per 100,000.
The Government currently uses a threshold of 20 cases per 100,000, along with a number of other criteria, when it makes decisions on whether to add or remove countries from its quarantine list.
Today's announcement by Mr Shapps means holidays are only currently possible without any restrictions at either end to Germany, Sweden, Italy, mainland Greece, Gibraltar, San Marino and Liechtenstein.
Transport Secretary Grant Shapps announced this evening that Poland and Turkey are being added to the travel quarantine 'red list'
The list of countries which UK travellers can visit without facing 14 days in self-isolation continues to dwindle.
The list of places Britons can travel to and return from without quarantining or taking Covid tests was already reduced to just nine last week.
Denmark, Iceland, Slovakia and the Caribbean island of Curacao were all removed from the safe list last Thursday.
There are still approximately 60 countries on the UK's 'green list' where quarantine is not required on return, but many of the nations have their own restrictions on arrival or are closed to visitors completely.
Downing Street remains under intense pressure to change the UK's travel quarantine rules amid growing fears for the future of the aviation and travel industries.
Ministers have faced calls for months to replace the current 14 day self-isolation restrictions for people returning to the UK from high risk countries with a more nuanced system of airport testing.
Advocates believe testing on arrival could open the door to significantly reducing the two week quarantine period to potentially less than seven days.
Mr Shapps reminded people that breaking self-isolation rules can lead to a maximum fine of £10,000
A double testing approach would see travellers tested on arrival and then told to self-isolate for something like five days when they would then be tested for a second time.
Two negative tests would be enough to allow people to end their period in quarantine and return to normal life.
However, ministers have been reluctant to approve airport testing because of concerns that the approach could fail to identify some people who have the virus.
This is because of the amount of time it can take for the virus to be detectable after the moment of infection.