Transport Secretary Grant Shapps has said he cannot provide figures on how many fines have been issued to people breaking quarantine rules, as more British holidaymakers face a scramble to return from popular destinations being removed from the safe travel list.

From 4am on Saturday, anyone returning from Croatia, Austria and Trinidad and Tobago will have to self-isolate for 14 days.

Mr Shapps said people travelling anywhere abroad this summer should keep their “eyes open” to the prospect of having to quarantine on return, pointing to his own experience of having been “caught out” when Spain was removed from the safe travel list while he was in the country last month.

Two-week quarantine rules for all UK arrivals came into force on June 8 to tackle the spread of coronavirus, with a number of countries added to and removed from the safe list – meaning self-isolation is not required – as the weeks have gone by.

Insisting quarantine checks are being made, Mr Shapps said his wife received a phone call “randomly” from Border Force after returning from their family holiday.

Asked on BBC Breakfast if anyone has been fined yet, he said “yes” but was not able to provide figures.

Asked if he is “curious” about how many people are abiding by the rules, he said “of course”, adding that Border Force will “in time” publish its information.

According to the latest available Home Office figures, as of August 14 nine fines have been issued at the border since quarantine restrictions were introduced.

Home Secretary Priti Patel last month said there had been a high level of compliance with the measures but in a report earlier this month the Commons Home Affairs Committee said it remained “unconvinced” by Home Office claims that an estimated 99.9% of the public subjected to quarantine restrictions were complying.

The latest restrictions came alongside some positive news for holidaymakers as Portugal was given safe travel status, meaning Britons will not have to quarantine on their return home.

Prices for flights from the latest quarantine nations have rocketed, with British Airways advertising tickets for an early Friday morning flight between Zagreb in Croatia and London at £276 for economy class. The same flight on Monday was £82.

Figures released by the Department for Transport (DfT) indicate the weekly Covid-19 incidence (cases) per 100,000 for Croatia increased from 10.4 on August 12 to 27.4 on August 19, a 164% rise.

Over the same period, Trinidad and Tobago saw a 232% increase, while Austria had a 93% rise between August 13 and August 20.

By comparison, the UK recorded 11.5 cases per 100,000 people in the seven days to August 16.

Croatia’s ambassador to the UK said it is “a regret” that the UK Government did not implement regional quarantine rules rather than removing the entire country from its exemption list.

Igor Pokaz told BBC Radio 4’s Today programme: “We regret that it was not possible for the UK Government to consider a regional approach, because in Croatia we have, as I said, witnessed these spikes in certain areas – for example in Zagreb in the capital and maybe among the young population.

“But in Dubrovnik, its surroundings and the islands there were very, very few cases. And I deliberately mention Dubrovnik and the islands as that is where most of the British tourists go.”

Mr Shapps told Sky News it is still “rather too difficult” to take a regionalised approach for other countries “because we just don’t have the same control elsewhere”.

It was put to Mr Shapps that someone returning from Croatia to Oldham in Greater Manchester, where the rate was the equivalent of 78.9 per 100,000 people in the seven days to August 17, is coming from a less dangerous situation to a more dangerous one.

The minister told the Today programme: “It clearly is a fact that there is regionalisation going on, localisation of the disease in different places in this country and elsewhere – that is undeniable.”

Warning that everyone should be aware of the changeable situation in terms of travelling anywhere, he told BBC Breakfast: “Regardless of where you’re going, having been caught out on this myself, everybody will be travelling with their eyes open this summer because this virus is incredibly unpredictable.”

In Scotland, travellers from Switzerland will also be required to quarantine for a fortnight on their return to the country.

Mr Shapps said while authorities are still reviewing the possibility of testing at airports, it is not a straightforward option.

Speaking to Sky News, he said: “I want to see systems in place to do that kind of thing. But you’ve also got to be sure that you’re testing the right person on that second time round because are you going to just send the kit to the house or are you going to require the person to perhaps drive to a test centre?

“So the point I’m making is this, it’s a bit more complicated than is sometimes suggested. People say why don’t you just test at the airport? Well, because it wouldn’t provide the results and you’ve then got to make sure the second test goes to the right person.”

Meanwhile, a group of MPs have urged Boris Johnson to adopt a “zero-Covid” approach to tackling the virus across England.

In a letter to the Prime Minister, the All-Party Parliamentary Group on coronavirus said the measure would “provide clarity and reassurance” to the public.

Group chairwoman, Liberal Democrat MP Layla Moran, said: “The Government has failed abysmally to put a clear strategy in place to eliminate coronavirus from the UK.

“This lack of clarity has left the public confused and our NHS and care staff flying blind.

“The Prime Minister must get a grip and introduce a comprehensive plan to control this deadly pandemic before this winter.”

Mr Johnson is currently holidaying in Scotland with his fiancee Carrie Symonds.

The Daily Mail has reported that the couple have been staying in a remote three-bedroom coastal cottage.

The Prime Minister did not return from his holiday last week when exams chaos erupted after thousands of pupils had their results downgraded.

According to the Mail, Mr Johnson was offered the opportunity to make a public statement regarding the situation, but Downing Street declined.