Among the chaos, one traveller tweeted she wished she had brought along a tent so she could camp out as the painstaking process took place.
Previously, the queues have been blamed on a lack of Border Force staff after some were forced to self isolate.
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Former Tory leader Sir Iain Duncan-Smith and James Gray, MP for North Wiltshire, called on the Border Force and Home Office to explain what is causing the “unacceptable” queues.
“They should explain what’s happening and why there are delays,” Mr Duncan-Smith told MailOnline.
“They are running a public service and they should be open to the public. Number one they’ve got to explain what the problem is and why they weren’t able to cope. Then we can work out what to do about it.”
Mr Gray said: “The Home Affairs Select Committee needs to get these people in front of them so we can find out exactly what’s going on. It’s their responsibility. The current situation is complete carnage. There’s no bit of it that’s acceptable.
“I cannot believe that all these people are self-isolating, I cannot believe there are not enough staff and I cannot believe Heathrow isn’t kicking and screaming about this.”
Welcome to UK with a veeeeeeery long queue and no water (or tea). My immigration bubble at Heathrow terminal 2. Should have brought a tent, a sleeping bag, and a mirror to see myself age in real time #Heathrow #Queenelizabethterminal #UKbordercontrol pic.twitter.com/j7VqfVaOaf
— Eshita Sharma (@eshitasharma10) September 7, 2021
Passenger Eshita Sharma tweeted on Monday evening: “Welcome to UK with a veeeeeeery [sic] long queue and no water (or tea).
“My immigration bubble at Heathrow terminal 2. Should have brought a tent, a sleeping bag, and a mirror to see myself age in real time.”
Ayushi Aruna Agarwal tweeted on Tuesday morning: “Hello from the immigration line at London Heathrow.
“They plan to make us spend 5 hours in close proximity with people from all over the globe here and then self-isolate for 10 days. Great plan.”
Dramatic images posted by travellers showed huge queues snaking around the airport.
The Home Office in statement blamed the queues on the need to check Covid documents - in addition to families with young children not being able to use e-gates because the facial recognition technology does not work with under-12s.
A Home Office spokesperson said: “Throughout the pandemic we have been clear that queue times may be longer as we ensure all passengers are compliant with the health measures put in place to keep the UK public safe.
“This weekend was the busiest of the year for returning passengers, with particularly high numbers of families with children under the age of 12 who cannot use e-gates.
“We have endeavoured to improve waiting times this week, for example by flexibly deploying staff across Heathrow Airport, and continue to work closely with all airports and airlines to make sure all passengers can have a safe and hassle-free journey.”
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