Dozens of flights have been cancelled or delayed at airports including Heathrow, Gatwick and Manchester as a widespread technical fault impacting air traffic control continues to cause chaos.
An error by a French airline has not been ruled out as the cause of flight chaos, No 10 suggested today.
Mark Harper, the Transport Secretary, added that the Government does not believe the disruption was caused by a cybersecurity incident, but an independent review will be carried out.
He noted that airlines would be stepping up to their responsibilities to ensure they get people home.
Holidaymakers were hit by travel delays on Monday after a system failure meant flight plans had to be input manually by controllers.
By Monday afternoon, 232 flights departing UK airports had been cancelled, as well as 271 inbound flights, according to aviation analytics firm Cirium.
Follow the latest developments below.