One in five people are still considering taking a holiday to foreign countries on England’s amber list, including Spain and Greece, despite stringent testing and quarantine requirements, polling has revealed.

The willingness to consider going to restricted destinations increases to a third of 18- to 24-year-olds, despite them being the least likely to be vaccinated, a survey by Survation showed.

Holidaymakers scrambled to get back from Portugal this week after it was switched from green to amber on the government’s traffic-light system, sparking criticism from holidaymakers and the travel industry.

Travel agents are calling for ministers to allow people who have had both doses of vaccine to travel to amber countries without testing and 10 days’ quarantine on return. The government has defended the system – which demands testing and quarantine for travellers from all but 11 countries and territories – saying it protects freedoms in the UK by restricting the spread of new variants.

On Monday, Matt Hancock, the health secretary, indicated greater travel freedoms were unlikely in the short term.

“Restoring international travel in the medium term is an incredibly important goal,” he told MPs. “It is going to be challenging and hard because of the risk of new variants.” The next scheduled reassessment of the traffic light categories is due on 24 June, but top European destinations including Spain, France, Italy and Greece all remain amber for now.

One of the UK’s largest tour operators, Tui, has cancelled all holidays to amber countries up to 20 June. Its chief executive, Andrew Flintham, has called for the government to reveal the methodology behind the traffic light decisions.

“There are destinations around the world with little or no Covid-19 cases and good vaccination rates, so we need to understand why these remain on the amber list,” he said.

Labour has said the amber list should be scrapped. Lisa Nandy, the shadow foreign secretary, said at the weekend: “We think it’s pointless. We think it’s confusing and that confusion is actually dangerous at the moment.”

The polling concluded on 2 June and was commissioned by Prenetics, a Covid testing company that was involved with test events including the Snooker world championship and Premier League football.

Abta, which represents travel agents, is calling on the government to scrap the need for testing to and from an amber destination country if travellers have received both doses of the vaccine. It also wants it to cut the costs of tests, including removing VAT charged on PCR tests, which can cost about £120 per person.

Asked about the public’s continued desire to go to amber countries, an Abta spokesperson said: “We are talking about the most popular overseas holiday destination on the amber list. We normally have 18 million people going to Spain each year. That’s why demand is strong and people really need a holiday. There’s a high percentage of the population that takes vacations overseas every year and they are really missing it.”

They said the difficulty of finding bookings in the UK now and the cost of UK holidays was also fuelling pressure to go to amber destinations.

A spokesperson for easyJet said: “Almost all of Europe has been placed into amber, and UK citizens may feel they have minimal viable options for a holiday but to book to an amber destination … Our research with Yale school of public health has shown that much of Europe is safe and should be on the green list, so we continue to urge the UK government to add more countries to the green list.”