Boris Johnson is believed to be hesitant to put France on the red list, having warned of a disruptive impact on trade and supply chains amid similar calls in March.

Contacted for comment, government sources stressed that they did not expect a decision to be made “in the near future”, adding that the data needed to be analyzed in more detail.

The number of beta cases recorded in France remains well below the peak seen in May, with the country’s overall case rate remaining low at 46.5 per 100,000. Nearly 50 percent of French adults have been fully vaccinated.

However, sources told The Telegraph that ministers and officials are alarmed that the variant will be reseeded in the UK this summer, as it is said to be more vaccine resistant than several other strains.

“They are worried about the South African variant because they think it escapes the vaccine, although they do not have proof yet,” said a well-placed figure. “This appears to be the reason why many countries in Africa and the Middle East are on the red list despite low prevalence rates.”

Other members of the government believe that as the delta variant continues to take hold across Europe, its greater transmissibility will lead to a decrease in the prevalence of other strains, thus reducing the argument for putting France on the red list.