Just three officials were seen on duty checking documents yesterday, leading to a backlog of hundreds of people crammed into a poorly ventilated room with ‘no social distancing’, said passengers.

The airport has admitted the situation was ‘totally unacceptable’, but said it was the responsibility of the UK Border Force who control the gates, MailOnline reported.

Natalie Crane, 32, from Surrey, had arrived back from a holiday in Majorca with her husband, mother, and three young children when she was faced with a two-hour delay.

She said: ‘We queued with about 500 or 600 people; there was no social distancing, no ventilation – it would have been impossible to socially distance that many people in the room. It was just barbaric.’

The mother said she couldn’t use the electronic gates because her children are too young so she was forced to join the long queues to see an officer in person.

She added: ’After a while we found out there was only three people on the counters checking passports, so then everyone started chanting “get more staff get more staff, this a disgrace”. 10 minutes later all of a sudden you’ve got about 10 staff on.

‘When we complained to one of the staff on the counters because he wasn’t making people aware he was available, his response was “don’t go on holiday”. There was no compassion from the staff whatsoever.’

The delays added to the misery of travellers whose holidays have already been impacted after the government said all those returning from Spain and Luxembourg will need to go into quarantine.

Natalie and her family will now have to self-isolate for 14 days after the rules changed while they were away.

The mum said she found out Spain had been taken off the list of countries British travellers are able to visit without the need to quarantine as she arrived there last Saturday.

She said she couldn’t understand why Majorca was included, given its low infection rate compared to mainland Spain.

Natalie said although the family made sure the news didn’t ruin the holiday, she added that it was ‘disheartening’ particularly as she had her young children with her.

Heathrow has been quiet for much of the summer as lockdown restrictions in place across the world led to a dramatic fall in the number of flights taking off. But queues returned at the start of the school summer holidays last week.

Other passengers have complained of long waits at passport control at the UK’s largest airport, without social distancing. Bosses have blamed people arriving for their flights too early.

All flights at Heathrow are currently only operating from two terminals – 2 and 5 – and the airport saw 280 planes arrive yesterday.

The Home Office has been approached for comment.