Thomas Cook has collapsed after last-minute negotiations aimed at rescuing the holiday company failed.
The UK Civil Aviation Authority (CAA) said that the tour operator has "stopped acting with immediate effect".
It has also triggered the largest peacetime repatriation ever aimed at bringing home more than 150,000 UK holidaymakers.
The tour operator's failure exposes 22,000 jobs worldwide, including 9,000 in the UK.
Travel expert Simon Calder spoke to the BBC from Manchester Airport about the situation that travelers and employees of the collapsed holiday company are facing.
Read more: Thomas Cook collapses when rescue calls fail