The government confirmed the introduction of a three-tier traffic light system for categorising countries for international travel to and from England at a briefing on Easter Monday.
Prime Minister Boris Johnson said he remains “hopeful” travel can “get going” from the earliest possible restart date of May 17.
However, confirmation of the restart date will only come nearer the time, with details of the classification of countries also expected nearer that date.
In the meantime, the government advised people “not to book summer holidays abroad until the picture is clearer”.
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The Prime Minister said: “I don’t want to give hostages to fortune or underestimate some of the difficulties we are seeing in some destinations.
“The Global Travel Taskforce is going to report later this week. We will be setting out before May 17 what we think is reasonable. We are not there yet.”
Asked how much notice the aviation industry could expect of the restart date, Johnson said: “We are going to give as much notice as we possibly can.”
The traffic-light system of green, amber and red was confirmed in a brief update on the work of the Global Travel Taskforce, one of four ‘roadmap reviews’ set up by the government.
This will see the introduction of a green list of countries to which holiday traffic is permitted without quarantine restrictions, but with pre-departure Covid-tests required before travellers return to the UK and a second test on arrival.
In practice, these will be the only destinations open to UK holidaymakers from the restart date.
How many countries will be on the green list to begin with remains unclear. Countries will be classified according to their vaccination rates, Covid-19 infection rates and prevalence of ‘variants of concern’ as well as their systems for tracking infections and variants.
A red-list of countries to which non-essential travel is banned and arrivals subject to mandatory hotel quarantine for 10 days will be retained.
Countries categorised as between green and red will be designated amber, with travellers subject to a combination of testing and self-isolation at home on return.
This category is likely to include most destinations for the time being.
Travellers returning from amber destinations will be required to self-isolate at home for 10 days and take three tests – one up to 72 hours before returning to the UK, one after two days and a third after eight days.
Quarantine may be cut short by paying for an additional test which proves negative after five days under the previously introduced ‘test to release’ scheme.
The testing requirements could be relaxed for travellers who have been fully vaccinated against Covid-19 with two vaccine doses, but details of how vaccination certificates will work are still being worked on with more details to come.
Johnson said: “The idea of vaccination status being useful for international travel is something all countries are looking at.”
But he added: “There are complicated ethical and practical issues around Covid status certification.”
Details of the requirements of the devolved administrations in Scotland, Wales and Northern Ireland have yet to be announced. However, the Scottish government has made clear it does not expect to allow a resumption of non-essential travel from May 17.
All the UK requirements will be in addition to the testing and quarantine restrictions in place in destination countries.
The government issued brief updates on the four reviews, including the taskforce and Covid-status certification.
The update on the taskforce stated: “The government hopes people will be able to travel to and from the UK to take a summer holiday this year, but it is still too soon to know what is possible.
“Given the state of the pandemic abroad, and the progress of vaccination programmes in other countries, we are not yet in a position to confirm that non-essential international travel can resume from that point.
“We will confirm in advance whether non-essential international travel can resume on 17 May, or whether we will need to wait longer before lifting the outbound travel restriction.
“When non-essential international travel does return it will do so with a risk-based ‘traffic light’ system. This will add to our current system a new green category with no isolation requirement on return to the UK – although pre-departure and post-arrival tests would still be needed.
“This new category will accommodate countries where we judge the risk to be lower, based for instance on vaccinations, infection rates, the prevalence of variants of concern, and their genomic sequencing capacity (or access to genomic sequencing).
“It is too early to say which countries will be on the green list when non-essential international travel resumes.
“These decisions will be driven by the data and evidence nearer the time, which we cannot predict now.
“In advance of the resumption of non-essential international travel, we will set out our initial assessment of which countries will fall into which category. Thereafter countries will move between the red, amber and green lists depending on the data.
“For the moment, the government advises people not to book summer holidays abroad until the picture is clearer
“The vaccination programme could offer a more stable route out of the need for such restrictions – provided we see sufficient efficacy against any variants of concern – which means the role of Covid-status certification is crucial to this work.
“The current intention is that, when non-essential international travel does resume, the NHS solution will facilitate international travel where certification is required, and we will look to establish arrangements with other countries and international organisations to establish mutual recognition of certificates.”
The announcement is likely to disappoint many in the industry who were hoping for more detail and greater clarity from the Prime Minister, leaving the extent to which travel will be possible to summer beach destinations around Europe in doubt amid the surge in Covid infections around the Continent.
However, the announcement leaves open the possibility of a gradual re-opening of borders in time for some peak-season travel.
The government is due to announce details of a review of social distancing rules and how these may be relaxed separately.
The briefing came after the government announced the extension of red-list restrictions to Kenya, the Philippines, Pakistan and Bangladesh from Friday April 9.
It also followed media reports that the Foreign Office and Department for Transport remain at loggerheads over the extent of guarantees to repatriate passengers required from the cruise industry before international sailings can resume.