BY Alix Culbertson, SKY News

Portugal travellers will no longer have to quarantine after a reduction in coronavirus cases over the past month.

Travellers coming from Croatia and Austria to the UK will now have to self-isolate for two weeks - while those coming from Portugal no longer face restrictions.

Anyone returning to the UK from Trinidad and Tobago will also have to quarantine for 14 days after cases on the Caribbean island more than doubled in a week.

The restrictions come into force at 4am on Saturday.

Transport secretary Grant Shapps also announced travellers returning from Portugal to the UK from 4am on Saturday will no longer have to self-isolate for two weeks.

The new quarantine measures apply to travellers going to Scotland from those three countries, with the Scottish justice minister announcing Switzerland is also on Scotland's list, but not for people returning to the rest of the UK.

The Foreign Office has said it would look at putting any country with more than 20 cases per 100,000 people on its quarantine list.

Croatia's average number of cases has risen to 29.5 cases per 100,000 people in the past week - compared to a rate of 13.54 per 100,000 a week ago.

The Mayor of Dubrovnik, one of Croatia's most popular tourist cities, said he had tried to speak to the British government to exclude travellers to the city from quarantine - as Germany has done - because he said it has had very few cases.

Mato Frankovic said he had hoped airport testing for coronavirus would be introduced in the UK instead of quarantine.

He told Sky News: "But we were not successful.

"I do hope those British citizens who want to come to Dubrovnik still do, and I want to send a very strong message that Dubrovnik is a COVID-safe town."

He said people immediately started cancelling hotel rooms when the quarantine was announced and for a city where Britons are the number one visitors, and Americans the number two, the decision will be devastating.

A scramble to leave Croatia, Austria and Trinidad and Tobago is expected after France saw thousands of British holidaymakers trying to beat the same deadline last week when it was placed on the quarantine list last Thursday.

The Netherlands, Monaco, Malta and Turks and Caicos were also placed on the quarantine list at short notice last week.

Spain and Belgium were already on it.

Trinidad and Tobago's cases have risen rapidly in the past week, with 25.81 cases per 100,000 people in the past week compared to 9.10 cases per 100,000 the previous week.

Austria's rate has nearly doubled in the past week, with 20.31 cases per 100,000 in the past seven days, up from 10.45 cases per 100,000 the week before.

A Department for Transport (DoT) statement said: "The government has made consistently clear it will take decisive action if necessary to contain the virus, which includes removing countries from the travel corridors list rapidly, if the public health risk of people returning from a particular country without self-isolating becomes too high."

People currently in Croatia, Trinidad and Tobago and Austria have been encouraged to follow local rules and check the Foreign Office's travel advice for more information.

"The government is urging employers to be understanding of those returning from these destinations who now will need to self-isolate," the DoT added.

Darija Reic, the Croatian tourist board's UK representative, said placing Croatia on the quarantine list is "very disappointing" as the UK market is integral to the Croatian economy, with 4.6 million overnight stays last year.

She told Sky News: "British guests are very important to us - for some areas such as Dubrovnik, it will not be the same without British guests.

"Since July, we've seen good growth in arrivals from the UK and the projections for the rest of the season were really good, however, this is an obstacle now that makes those goals less achievable."

Portugal's government and tourist industry expressed anger when the country was placed on the quarantine list when it was created at the beginning of July.

The country's number of cases dropped in the past week to 14.38 cases per 100,000 people, compared to 15 per 100,000 the week before - and has not been over 20 per 100,000 since the week of 15-22 July.

In many other parts of Europe there has been an increase in cases:

• The UK had 1,182 new cases on Thursday
• Italy recorded 845 new cases on Thursday, the highest daily increase since lockdown was eased
• France had 4,771 cases on Thursday, compared to 3,776 on Wednesday
• Spain reported 3,349 cases on Thursday - more than 1,000 in Madrid
• Germany recorded 1,707 cases on Thursday - the largest daily increase since 26 April.