Air passengers were facing lengthy delays in Britain on Tuesday after a computer glitch hit British Airways check-ins and protesters from "Black Lives Matter" forced their way on to the runway of London City Airport.

British Airways said it was taking longer than normal to process customers at Heathrow and Gatwick near London but did not comment on social media reports that there were also major delays in San Francisco, Washington D.C. and Atlanta.

The airlines then prompted its staff to issue passengers with handwritten boarding passes in order to keep flights operating.

BA, owned by International Consolidated Airlines Group, apologized to customers for the delays and urged passengers to check in online before they reached the airport.

Meanwhile, irriated passengers turned to social media to complain of delays:

(With Inputs from Reuters)