Passengers at Heathrow Airport faced hours of queuing during the Bank Holiday weekend.
Holidaymakers complained of staff shortages and no social distancing at the airport.
Families were forced to wait for up to four hours to pass through border control on Sunday as Border Force carried out extra spot checks under the government’s latest entry requirements.
Heathrow Airport confirmed Border Force had been experiencing delays on Twitter.
Chaotic scenes saw pregnant women standing in line, parents trying to entertain their children and one mother rationing a bottle of milk for her baby.
Border Force officials were told they no longer need to make Covid checks for those arriving from green and amber list countries in an attempt to reduce queues, according to reports.
However, travellers vented their frustration when they realised only one quarter of the desks were open to handle hundreds of passengers.
Among the sea of people, one mother explained how there was no queue for the eGates but those unable to use it including adults with children were funnelled into an exhaustive three-tier queue system.
The woman, travelling from Zurich, Switzerland, told the Evening Standard: “Families were waiting hours. You had people with babies, young children, pregnant women, all just stuck.
“We had planned for this possibility and my kids, at nine and seven, had fully charged games consoles and a bag of snacks, but lots of people had little to occupy their children.
“Anyone who had checked their buggy was having to hold their child the whole time and I saw at least one mother ration a bottle of milk she had for her baby.
“It wasn’t that there were too many passengers, or that document checking was taking a long time. There just simply weren’t enough staff and most of the desks were not open.”
Passengers reported just two out of eight border control desks were operational at Terminal 2.
Some travellers praised Heathrow staff for handing out water and doing what they could to assist while others criticised waiting conditions.
Among the people waiting, one person said: “This is brutal. Families with young kids forced to queue for two to three hours, standing, no food or water beyond what you’ve brought off the plane.
“Yes, it’s border force setting the rules but it’s Heathrow controlling conditio
Another said: “Our flight GQ700 arrived at 1.45pm together with other two flights. Four hours in the line, without Covid measures or special attention for women and kids.”
A spokesperson added airport staff do give out water every day as a matter of procedure and this was primarily a border force issue.
Seven countries were added to the green list including the Azores, Canada, Switzerland, Denmark, Finland, Lithuania and Liechtenstein meaning returning Britons will no longer have to quarantine from 4am on August 30.
Thailand and Montenegro were bumped up to the red list requiring arrivals to stay at a quarantine hotel for ten days.
A Home Office spokesperson said: “Our utmost priority is protecting the safety and health of the public. That means, occasionally, passengers will need to accept an increase in the time taken to cross the border, especially during peak travel periods.
“We will never compromise on border security and continue to fulfil our vital function of keeping the border secure while checking that passengers are compliant with the current health measures.
“Border Force officers are redeployed to provide support as and when required, and are playing a vital role by working round the clock to support arrivals from Afghanistan.”