Electronic passport gates have gone down across UK airports.
The issue is likely to cause long delays for bank holiday travelers as all airports across the country that use the gates are affected.
The Home Office has confirmed the news - but did not say how long the fault would last.
A Home Office spokesperson said: "We are aware of a nationwide border system issue affecting arrivals into the UK.
"We are working to resolve the issue as soon as possible and are liaising with port operators and airlines to minimise disruption for travellers."
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