Travelers heading to London Heathrow Airport faced disruption on Tuesday because of the closure of a main road tunnel at the biggest UK hub, less than a week after a UK-wide air-traffic control failure canceled some flights.

Travel chaos broke out at Heathrow on Tuesday morning after a key road tunnel was closed. The tunnel, which holidaymakers use to drive to Terminals 2 and 3, was closed at 9.30am because of a “technical issue”.

Heathrow Airport has been plunged into chaos as the closure of a tunnel to Terminals 2 and 3 left hundreds of passengers trapped. The London airport issued a statement in which it apologised to travellers for the disruption.