Transport Secretary Grant Shapps was today urged to launch a task force to slash border delays at major airports before international travel restarts.
Industry experts fear huge queues at frontiers once non-essential overseas trips are allowed – probably from May 17 – as coronavirus curbs are eased.
Today it was reported the updated NHS app which will feature vaccine passports will not be ready by the May 17 deadline.
Officials have highlighted six-hour waits at Heathrow as under-pressure staff manually check passengers' documents.
Delays have mounted because the electronic gates at borders cannot be used as they cannot check passenger locator forms and details of coronavirus test results.
Insiders fear the situation will worsen once more travel is permitted.
Heathrow chief executive John Holland-Kaye warned flights could be turned away unless the Government “gets a grip” of the fiasco.
Border Force was “struggling to cope even with the few thousands of passengers who are coming in at the moment,” he told Sky News.
Mr Holland-Kaye added: “Border Force and the Home Office need to get a grip on this before May 17 so that immigration does not become a stranglehold on the economic recovery.”
The airport had already had to turn away a small number of flights because of concerns over queues – and the same could happen in future, with flights potentially diverted to other airports in the UK or even abroad, he added.
“That is distressing for anybody travelling and would be an embarrassment for the UK Government,” said the boss.
Mr Shapps was quizzed about the delays in the Commons.
Shadow Transport Minister Mike Kane told MPs: “Border Force is operating an onerous, manual, assurance-check on inbound passengers' Covid compliance, despite there being very low incidences of non-compliance and robust pre-departure checks by carriers – causing huge queues in our immigration ports.
“The Transport Secretary likes his task forces – where is the one to alleviate these bottlenecks before our skies reopen on May 17?”
Mr Shapps said: "As we move towards the unlock of international travel we will be addressing this issue, not least through beginning to automate the electronic e-gates with the pre-departure form."
He said “both hardware and software” were needed “to automate those gates”.
The devastation to the aviation industry caused by the pandemic was highlighted as the company behind Heathrow revealed another £329million loss in the first three months of 2021, as only 1.7 million passengers travelled through its terminals – down 91% compared to two years ago.
It takes to £2.4bn the total amount the airport has lost from Covid-19.
Mr Shapps was also quizzed about the cost of polymerase chain reaction tests which passengers will need to take.
Experts have warned they are too expensive, with some costing £120.
But the Cabinet Minister said one company on the Government's approved list is selling a single PCR test for less than £45.