Ministers are considering adding France to the travel red list, The Telegraph has learnt, with officials ordered to conduct a "deep dive" into data concerning the spread of the South African/beta variant.
Senior Whitehall sources said the proposal was discussed at a meeting on Wednesday as part of the review of international travel, which saw the Balearic Islands demoted to the amber list only a fortnight after turning green.
Insiders with knowledge of the discussions said the recommendation to move France from amber to red, requiring all arrivals to undergo hotel quarantine for 10 days, was based on an analysis by the Joint Biosecurity Centre (JBC).
Officials are said to be alarmed about the prevalence of the beta, or South African, variant in the country, which is said to be significantly higher than levels globally.
But others with knowledge of the meeting said there were "mixed opinions" about how to deal with the situation, with ministers agreeing to monitor it closely.
The JBC and the Department for Health have been asked to "interrogate" data coming out of France. A number of meetings are expected to take place in the coming days, with sources signalling on Thursday night that the situation could be discussed at a meeting of the Covid-O Cabinet sub-committee as early as Monday.
Coronavirus France Spotlight Chart – Cases default
It is thought that Boris Johnson will be reluctant to place France on the red list, having warned of a disruptive impact on trade and supply chains when faced with similar calls in March.
Approached for comment, government sources stressed that they did not expect any decision to be taken "imminently", adding that the data needed to be analysed in more detail.
The number of recorded beta cases in France remains well below the peak seen in May, with the country’s overall case rates remaining low at 46.5 per 100,000. Almost 50 per cent of French adults have been fully vaccinated.
However, sources have told The Telegraph that ministers and officials are alarmed at the prospect of the variant being reseeded in the UK this summer, as it is believed to be more resistant to vaccines than several other strains.
"They are worried about the South African variant because they think it escapes the vaccine, although they don’t have evidence of that yet," a well-placed figure said. "It appears to be why a lot of countries in Africa and the Middle East are on the red list despite low prevalence rates."
Others in the Government believe that as the delta variant continues to take hold across Europe, its greater transmissibility will mean other strains fall in prevalence, reducing the argument for putting France on the red list.
Travel countries on the red, green and amber list
Alternatively, if the beta variant continues to spread, it has been suggested the Government could issue guidance to holidaymakers asking them to consider the risks of travelling to France.
It comes just 24 hours after ministers were accused of throwing holiday plans for tens of thousands of young Britons into disarray by announcing that Ibiza, Mallorca, Menorca and Formentera would lose their quarantine-free status from Monday.
The British Virgin Islands will also be demoted to the amber list, despite only being put on the green list at the end of June.
Other changes include Bulgaria and Hong Kong going green, while Croatia and Taiwan will be added to the green watch list. Travel experts described the change to Hong Kong’s status as "pointless" because the territory requires Britons to quarantine on arrival.
Cuba, Indonesia, Myanmar and Sierra Leone will be added to the red list, meaning 10 days of isolation in a quarantine hotel are mandatory.