Health experts have supported the Government’s cautious approach in opening up international travel through a traffic light system, with one describing it as “sensible”.

Portugal, Gibraltar and Israel are among just 12 destinations which will be on the quarantine-free green list from May 17 in England – with some countries on the list still not accepting holidaymakers.

Holiday hotspots Spain, France, Italy and Greece have been added to the amber list – destinations which people are advised not to travel to, and from which arrivals must self-isolate at home for 10 days and take two post-arrival tests.

Transport Secretary Grant Shapps said on Friday that the removal of the ban on international leisure travel is “necessarily cautious” and that the Government must “make absolutely sure” the countries the UK reconnects with are safe.

Linda Bauld, professor of public health at the University of Edinburgh, supported the cautious approach, describing how last week there were more cases of Covid-19 globally than at any point of the pandemic.

“I know people are disappointed that they can’t go to France or Spain, but at the moment if I could point to one area that I’d be most anxious about, it would be variants and importation of infection,” she told Times Radio.

“I think that’s the territory we have to be most cautious and move most slowly.”

Her sentiments were echoed by virologist Dr Chris Smith, who warned that measures should not “endanger, imperil or undermine” the good work done so far with the vaccination programme in the UK.

Speaking to BBC Breakfast, he said: “The measures that have been put in place I think are sensible, I think they are measured measures at the moment.

“But it is an unknown bit of territory we are going into, so it’s important we take small steps and have measures in place to measure what we’re doing.”

He encouraged the public to be patient and described the measures as “short term” as he pointed to a surge of cases in India.

“We are seeing in our country right now imported cases of a variant from India which is spreading,” he said.

“What we don’t want to do is send people who have been vaccinated overseas, because if you think about it, the only case of a virus coming back with one of those people is going to be one that can bypass the protection conferred by their vaccine.

“So they could potentially bring that back and start it spreading across the country.

“These are all measures that will work for now, they’re not going to be here forever, I think we just have to sit tight for a little bit longer.”

It comes as the Government faced pressure from travel industry bosses to clarify when other holiday destinations could be added to the green list.

Airlines UK, an industry body which represents UK carriers, said the Government must make “major additions” to the green list at the next review point in three weeks.

Meanwhile, those travelling from countries on the red list to England after 4am on Wednesday will be required to stay in a quarantine hotel for 11 nights at a cost of £1,750 for solo travellers.