Holidaymakers could face six-hour airport queues and border chaos lasting weeks as quarantine rules are scrapped for those travelling back to the UK, it has been claimed.
Transport Secretary Grant Shapps confirmed double-jabbed people can visit amber-listed countries without having to self-isolate for 10 days on return home as of Freedom Day on July 19.
But insiders are reported to have warned extra checks could see queueing times soar as airports and Border Force scramble to get ready in time.
Lucy Morton, of Immigration Service Union, said today checking Covid documents can take up to 12 minutes per passenger and said queuing times could come down to how prepared each traveller is on arrival.
It comes as airlines are already seeing a surge in flight bookings, including a 400 percent jump for easyJet.
It added 145,000 extra seats for the summer, while competitor British Airways reported website traffic traffic close to doubled after Mr Shapps' Commons announcement on Wednesday.
For sun-starved Brits who have had both vaccinations, the decision effectively turns the 147 destinations - including Greece, Spain and Portugal - on the amber list to green.
Tourism leaders and MPs have, however, warned that the current cost of testing remains a "barrier" to foreign travel for many families going on holiday.
Mr Shapps said during his announcement the much-anticipated change to travel rules could lead to major queues at airports in the UK and abroad.
A Whitehall source has told the Daily Mail that Border Force is "nowhere near ready" to cope with the overhaul and predicted the agency won't have upgraded its system until August.
"You could easily be looking at queues of six hours to start with," they said.
"The Border Force is nowhere near ready. What no-one knows is how much extra traffic there will be as a result of the change."
Lucy Morton told BBC Radio 4 this morning the UK is currently seeing peak time queues at around the "1-2 hour mark" as several aircrafts arrive at the same time.
"Exactly how long you're going to have to wait depends on where you're flying into, how many other people have flown in at the same time and also how ready the other passengers around you and on other aircraft are."
She said whether passengers have the right documentation ready can determine how quickly queues move.
"It takes about three-four times longer to check somebody's Covid documentation that it would to check them for border purposes," she added.
It comes after airport queues at Heathrow surged to seven hours despite passenger numbers being at just 15 percent of pre-Covid levels.
Meanwhile, the Foreign Office has also now axed travel advice warning against non-essential travel to 23 destinations, with the likes of France, Greece, Spain and the US among them.
Meanwhile, the Foreign Office currently advises against non-essential travel to the majority of amber-listed countries, meaning insurance policies are invalidated.
But it remains unclear if all amber-listed destinations will see the same before the rules change.
Former PM Theresa May called on Mr Shapps to boost border resources to help reduce long queuing times.
The Transport Secretary responded: "Quite a lot of the check-in would be done before you board the aircraft, or what could also be a train or boat, from the location you're coming back from.
"And so the queues at check-in, while you're abroad, may in fact be the place where those problems most exist.
"I know that many of the airlines are developing systems to further automate that check-in, but they will be doing quite a complicated job."
Asked about the potential for chaos at the UK-French border, he went on to say that additional checks "are likely to cause delays" on both sides of the Channel this summer.
"People will want to prepare and plan their journeys with supplies and also ensure that they have picked the best time of day to travel in order to avoid it," Mr Shapps added.
MP Huw Merriman urged ministers to consider allowing travellers to use more affordable rapid tests upon returning to England, in place of the PCR tests.
But the Transport Secretary said "scientific evidence" showed the more expensive tests were needed to detect variants of concern.
