Officers will no longer routinely verify arrivals have tested negative before departure or completed a passenger locator form, the ISU said.

The Guardian first reported the change and said it aimed to reduce queues.

The government said carriers were checking all necessary requirements including forms and test bookings.

A spokesperson added: "This legal requirement on carriers is underpinned by a robust compliance regime, which is overseen by regulators.

"Compliance with these rules is essential in order to protect the population from new variants of Covid-19, and so there will be tough fines for those who do not follow the rules."

Airlines UK, which represents easyJet, Tui and British Airways among others, said: "Carriers are committed to working with Border Force on these requirements, which is why compliance has remained consistently extremely high."

But Labour's shadow home secretary Nick Thomas-Symonds accused the government of "yet more staggering incompetence" and added: "They must - urgently - get a grip."

From Monday, carriers were asked to begin checking vaccine status certification. They were already legally required to ensure passengers have completed necessary requirements before travelling.

The Guardian said it had seen a leaked memo that told border staff they no longer had to search for a passenger locator form when the computer system failed to find one.

The memo also reportedly confirmed that electronic border gates "will no longer refer passengers to in-person checks by Border Force officers if a passenger locator form is not found".

The memo, which the Guardian said became operational on Monday as other restrictions eased in England, has not been seen by the BBC.

Border Force officers were previously instructed to check 100% of passenger Covid documentation at the border - a direction blamed by some for contributing to queues of up to six hours.

Previously about 10% of passenger Covid documentation had been checked.

But Lucy Moreton, of the ISU trade union, confirmed the reported memo was accurate.

"Ultimately this is a political decision," Ms Moreton said.

"Certainly, it will reduce queue times significantly and hopefully also the level of verbal abuse to which Border Force staff are subject.

"That is welcome to us. The impact on the UK's Covid security is ultimately a scientific determination."

Disruption warning

Transport Secretary Grant Shapps has warned of continuing disruption to travel, saying passengers should expect much of that to be focused at check-in and before travel, rather than at the border.

All arrivals regardless of where they are coming from abroad are required to test negative before departure and have valid proof of their test status.

They are also required to conduct another test two days after their arrival, and prove this is organised pre-departure.

All travellers to the UK must complete a passenger locator form with basic details including an address.

Those arriving from amber list countries, who are not fully vaccinated, must also complete a further test on day eight and quarantine at an address listed on the form.

People who have been fully vaccinated are no longer required to carry out home quarantine when arriving from an amber list country.

Arrivals from red list countries must quarantine in a government-approved hotel for 10 days, at a cost of at least £1,750 per adult.