Passengers travelling into the UK experienced hours of delays at airports throughout the country due to faulty passport e-gates.
Passengers expressed frustration at being stuck in long lines at airports such as Heathrow, Manchester, and Gatwick.
On Saturday evening, the Home Office said that all e-gates were back up and running.
A source informed the BBC that the outage, which began on Friday night, was caused by an IT problem.
All airports in the country that used the technology were affected.
By allowing some travellers to scan their own passports, the e-gate technology expedites passport control. It employs face recognition to authenticate identity and takes a picture of the traveller.
Passengers coming into the UK had to have their passports manually verified, with larger airports with e-gates being the most affected.
Marc Baret was scheduled to fly from Chicago to Manchester through Heathrow, but he changed his plans after spending more than two hours waiting at the London airport.
“It was absolute chaos at passport control,” he claimed. People were becoming agitated, and a couple of people attempted to skip lines, prompting the police to intervene, and one of the passengers fainted.”
Another person landing at Gatwick described the scene as a “absolute farce.”
Stephen, who declined to give his second name, sat at Bristol airport for two and a half hours on Saturday afternoon without access to water.
“It was very hot,” he added, adding that there was just one water bottle filling station in the Arrivals halls and none in the immigration hall itself.
“Because I didn’t have a water bottle to refill, I was extremely thirsty afterwards.”
Eurostar passengers were also inconvenienced, with passengers waiting in long lines at Paris Gare de Nord railway station due to malfunctioning e-gates.
One man reported he had to wait in line for more than two hours at Luton Airport. Craig Pullen also told the BBC that it was “very poor” that passengers were not given regular updates on the situation or told how long it would take to cross passport check.
Bobby Lane spent three hours at Luton Airport’s passport check in the early hours of Saturday morning.
He commended a Bedfordshire police officer who handed out water bottles to stranded passengers, saying that he “kept thousands in line with humour and kindness.”
According to an airport official, the atmosphere among passengers was “one of patience and understanding.”
Dave Tatlow was one of 300 travelers trapped in a Heathrow Airport line early in the morning.
He said that some people had overheated in the hot glass structure.
“An elderly gentleman in his seventies who was traveling alone collapsed and had to be helped by other passengers and staff.”
“After that, bottles of water were distributed.”
This weekend was predicted to be busy for travelers, as the bank holiday coincided with many families’ half-term break.
Separately, passengers departing the United Kingdom from the Port of Dover encountered difficulties as the French passport system failed early on Saturday.
That problem has since been resolved, but automobiles and coaches had to wait for approximately an hour while 400 lorries waited to cross.
According to Lucy Morton of the Immigration Services Union, depending on the airport, 60-80% of inbound travelers use e-gates.
“There’s no impact on national security,” she stressed, stressing that all arrivals would have been thoroughly scrutinized at officer desks.
E-gates can be used by British nationals over the age of 12, EU citizens, and residents of countries like as Australia, Canada, the United States, Japan, and New Zealand.
However, manned security desks remain at all entrance points for other passengers and those who are unable to utilize e-gates.
British Airways was also affected by IT troubles on Thursday and Friday, affecting almost 20,000 passengers at Heathrow.
