But by the time border measures were strengthened again, a number of omicron cases had already been identified across the UK. They quickly multiplied, leading to widespread community transmission and omicron replacing delta as the dominant virus strain within a fortnight.

Despite omicron now accounting for almost all cases in Britain, the border testing regime is continuing to have a significant impact on the aviation and travel industry, which has warned that the additional expense and bureaucracy is proving a “major deterrent” to travel.

Urging Boris Johnson to drop the requirement, Sir Graham told The Telegraph: “The PM made the right call over Christmas and New Year, trusting people to make the right choices in their own lives and throwing a lifeline to the struggling hospitality sector.

“We now need to see this extended to international travel, which is facing yet more restrictions at a crucial time in the booking season. We need to see consistency and, if a more relaxed approach is good enough for the domestic economy given what we know about Omicron, it should be good enough for travel too.”

He was joined by Henry Smith, the Tory chairman of the all-party parliamentary group on aviation, who said: “International travel can’t be the forgotten sector as we learn to live with omicron. We long ago had community transmission in the UK, and thankfully the data on severity is looking positive.

“These emergency restrictions simply aren’t required any longer, but every week they are imposed means more money lost to the Treasury, a further erosion of our international competitiveness and jobs threatened.”

Tim Alderslade, the chief executive of Airlines UK, said: “We can’t have international travel – and the hundreds of thousands of jobs and livelihoods that depend on it – being treated differently to hospitality and other domestic sectors.

“If omicron doesn’t warrant further restrictions at home, then the case for continuing with testing for aviation beyond Jan 5 is undermined, especially now it is the dominant variant in the UK. We need consistency, not favouritism.

“Tens of billions of pounds of Treasury revenue depends on getting this sector moving again, not to mention the ability of families across the country to get away this half-term. There are some amazing deals out there – but this redundant testing is what is killing demand.”