Luggage piled up at Heathrow’s Terminal Five after a technical fault put the airport conveyor belts out of action.
Staff struggled to clear the backlog of bags on Friday as passengers took out their frustration on British Airways, the only airline to use the terminal.
Airport bosses admitted that some of the baggage had failed to make it through but promised to get the bags back to their owners as soon as possible.
A spokesman for Heathrow said on Friday: "We are experiencing intermittent issues with the Terminal 5 baggage system which has caused some bags to be processed manually.
"While passengers can currently check-in bags our engineers are still working to identify the root cause of the problems. Passengers may wish to carry essential items in hand baggage where possible.
"Manual processing has led to some bags not making flights in time. We are very sorry for any passengers affected and we are working with airlines to reunite passengers with their bags as quickly as possible."
A British Airways spokesman told the Daily Mail: "On Thursday morning, the baggage system in Terminal 5 suffered an IT problem which affected how many bags could be accepted for each flight.
"We are very sorry for the difficulties this has caused and we have been working hard with the airport to make sure we reunite all of our customers with their luggage as quickly as possible."
