The United Kingdom refused on Thursday to scrap its requirement for arrivals from France to serve 10 days in quarantine, despite claims from scientists it was unnecessary.

The rule took effect on Monday, after fears grew that the Beta variant of the novel coronavirus, which was said to be especially virulent and circulating widely in France, would enter the UK without it.

But the Financial Times newspaper reported on Thursday the Beta variant is no more virulent than many other strains, and is harder to catch than the Delta variant that is prevalent in the UK and becoming the dominant strain in France.

Florence Debarre, a biologist at France's state-owned National Center for Scientific Research, told the paper at least a dozen countries have higher proportions of the Beta variant than France, but are not subject to the UK's quarantine rule.

Sylvie van der Werf, a molecular geneticist at the Institut Pasteur, told the Financial Times she too was "puzzled" by the UK's decision to single out France.

"The only reason-and it's questionable still- is the variant's higher immune escape," she said, while noting that some research suggests the Beta variant is more resistant to vaccines than other strains, and to the AstraZeneca jab in particular, which is widely used in the UK.

Indeed, The Guardian newspaper reported in February that one study suggested the Beta variant lowered the efficacy of the AstraZeneca vaccine to 10.4 percent.

Some experts have said the UK may have singled out France because London's data was skewed by France's overseas territories-including the islands of Martinique and Guadeloupe in the Caribbean, and Reunion in the Indian Ocean-having high rates of the Beta variant.

The Daily Mail newspaper said rates are, however, falling in France and rising in Spain and Greece, which will only add to the pressure on Health Secretary Sajid Javid to think again.

British Airways chief executive Sean Doyle told The Independent: "Our successful vaccination program-including effectiveness against variants-should have given us the confidence to get back in the air, but the goal posts are constantly shifting."

However, London said on Thursday it will continue to insist upon arrivals from France completing 10 days of quarantine, even if they have been double-jabbed.

The UK said France has registered 2,959 cases of the Beta variant, which is 5.2 percent of its total number of cases. London said that suggests the variant is almost three times as prevalent there as it is in the UK.

The UK's Department of Health and Social Care said in a statement: "France has the second highest percentage of Beta cases in the world, following South Africa."

The Independent newspaper added that, regardless of the current situation, the Beta variant is likely to fade globally in the coming weeks.

Data uploaded to the Global Initiative on Sharing All Influenza Data shows very few countries are now detecting the Beta variant.

The paper said that in mid-March, around 2 percent of all global cases involved the Beta variant, but by mid-July, the number was down to just 0.4 percent. The Delta variant, which accounted for 0.1 percent of infections in mid-March, now accounts for 70.4 percent. The Alpha variant remains widespread.

Aris Katzourakis, a professor of evolution and genomics at Oxford University, told The Independent: "So, it's likely to be outcompeted by both Alpha and Delta in vaccine-naive populations."