The decision to impose restrictions on fully vaccinated Britons returning from France over concerns about the beta variant has been called into question, after it emerged an Indian Ocean Territory which is a hotspot for the strain is not covered by the new rules.

Under changes to home quarantine regulations, which come into effect on Monday, people returning from France will still have to isolate at home for up to 10 days, despite the rules being relaxed for all other amber list countries.

The last-minute change, announced on Friday, was made in response to mounting alarm at the prevalence of the beta variant, which originated in South Africa, which is believed to be more resistant to covid-19 vaccines.

The move has thrown holiday plans for tens of thousands of Britons into disarray and has infuriated the travel industry, which has warned that the system is undermining efforts to reopen international travel.

There are now fears among travel experts that Spain, Greece, Belgium, Netherlands and Germany may soon follow France and face additional restrictions.

However, changes to public health regulations published on Sunday have revealed that the added restrictions, dubbed “Amber Plus”, will only cover mainland France, meaning the traffic light ratings of its overseas territories will remain unchanged.

The regulations refer only to “metropolitan France”, with officials confirming that Réunion, the Indian Ocean island near Madagascar, will remain on the amber list.

It means that double jabbed Britons who travel to Réunion will not have to quarantine at home on their return, despite figures suggesting that the overall prevalence of covid-19, as well as the beta variant, are much higher on the island.

There are now 69 cases per 100,000 people in France, although cases have surged in the past week, with an average of 6,687 new infections now reported per day, according to Reuters covid-19 tracker.

Coronavirus France Spotlight Chart – Cases default

Gisaid, a website that tracks Covid variants, says the beta variant represents just 3.4 per cent of cases in France over the past four weeks, although Cabinet minister Robert Jenrick on Sunday suggested it currently ranged from between 5-10 per cent.

But it appears that data used by the Government to inform its decision on imposing additional measures on France included data from Réunion, where approximately 167 out of 100,000 people have Covid-19 and the variant is believed to account for almost 100 per cent of cases.

The beta variant is also dominant in another French Indian Ocean island of Mayotte, although the overall Covid rate is only at 6 cases per 100,000.

Travel countries on the red, green and amber list

The Department for Health on Sunday suggested that the data used did include France’s overseas territories, although sources insisted that the mainland’s level of beta variant prevalence was the primary reason for maintaining the self-isolation requirement for France.

However, it remains unclear as to why Réunion and Mayotte are not also facing the same restrictions.

The disclosure is likely to spark a fresh backlash from Conservative MPs, who have already accused ministers of hampering “any meaningful recovery for our aviation, travel and tourism sectors.”

Meanwhile, it was reported on Sunday that emergency road measures to handle post-Brexit queues in Kent have been restarted by the government to cope with potential holiday traffic.

Barriers on the M20 were erected over the weekend for Operation Brock, a decision taken on Thursday “in anticipation of increased international travel by car drivers from Monday”, according to Highways England.

Paul Charles, the the chief executive of travel consultancy The PC Agency, told the Telegraph: “There’s no consistency and the French know that the rates are high in Reunion, so why is the Government not covering Reunion? It just supports the notion that the policy is out of control.

“It just proves that there is enormous inconsistency in the traffic light system and the sense that the Government is making it up as it goes along.”

Henry Smith MP, the chairman of the All Party Group on aviation, added: "It seems like these decisions are not backed up by the evidence, which either suggests they are making them on the hoof or are not using the data consistently."