Downing Street has warned people should not be holidaying in “amber list” countries after a senior minister suggested they could travel to visit family or friends.

Following the ending of the ban on foreign holidays on Monday in the latest easing of lockdown restrictions, Environment Secretary George Eustice said people could go to those countries if they observed quarantine rules on their return.

“We don’t want to stop travel altogether and the reason, as (Health Secretary) Matt Hancock set out, that we have the amber list is there will be reasons why people feel they need to travel either to visit family or indeed to visit friends,” he told the BBC Radio 4 Today programme.

“They can travel to those countries but they then have to observe quarantine when they return and have two tests after returning.

“So people can travel to those areas, yes, but they will then have to subject themselves to the quarantine requirements on return.”

But at the daily briefing for political journalists, the Prime Minister’s official spokesman insisted travel to amber list destinations was only permitted for a strictly limited number of reasons.

He said that people should still not be going to those countries for holidays or leisure purposes.

“The position remains that people should not travel to amber list countries and that is to protect public health,” the spokesman said.

We are keeping a careful eye on this and we will take further action if necessary

“There are some limited reasons why it might be acceptable to travel – for work purposes, protecting essential services or compassionate reasons such as a funeral or care of a family member – but otherwise people should not be travelling to these countries.”

Speaking during a visit to a vaccination centre in north London, Boris Johnson said: “I think it’s very important for people to grasp what an amber list country is: it is not somewhere where you should be going on holiday, let me be very clear about that.

“And if people do go to an amber list country, they absolutely have to for some pressing family or urgent business reason, then please bear in mind that you will have to self-isolate, you’ll have to take tests and do your passenger locator form and all the rest of it.”

The warning came amid reports that thousands of people had headed for destinations such as France, Greece, Spain and the United States, with more than 150 flights reported to have departed on Monday.

The Prime Minister’s spokesman said that as the country moved to a situation where people were able to exercise greater personal responsibility with regard to the coronavirus restrictions, it was important to proceed with caution.

He said that holidays and leisure travel should still be restricted to the short “green list” of safe destinations such as Portugal.

“We are working with the travel industry and others on this. All of us have a personal responsibility to protect one another as we cautiously reopen international travel,” the spokesman said.

“That is why it is important when proceeding to go on something like a holiday people stick to the green list.

“We are moving to a situation where the public can take responsibility for their actions. I think it is important to stress that by and large that is what we are seeing.

“Obviously we will keep this under review, we are keeping a careful eye on this and we will take further action if necessary.”

For Labour, shadow home secretary Nick Thomas-Symonds said the Government’s border had “unravelled into dangerous chaos” within hours of travel opening up.

“There is a lack of strategy, which has meant the UK Government, and their own ministers, are giving out conflicting and confused advice about whether people are allowed to travel, especially between amber list countries.”