A fault on UK Border Force computers, including automatic passport check-in desks, caused systems to crash late this evening, causing widespread chaos for passengers at airports such as Heathrow, Gatwick, Stansted and Birmingham.
Extra staff were drafted in to try and reduce the queues.
Passengers tweeted their frustration through the evening:
A Government spokesman said: "We apologise for any additional time this adds to passengers' journeys."
More top news
Two distraught dog owners have been reunited with their beloved pet pooch - seven years after she was stolen from their home.
David Cameron hasn't repeated his migrant 'swarm' comment since his interview with ITV News, but he's likely to be reminded of it.
Breaking Bad fans can relive the adventures of Walter White - only with no actual drugs - thanks to a new novelty café in Turkey.