Thomas Cook has ceased trading today after last-minute talks to save the 178-year-old holiday firm failed.
The UK Civil Aviation Authority (CAA) said the tour operator had “ceased trading with immediate effect”.
This has left 150,000 British holidaymakers stranded.
Peter Fankhauser, Thomas Cook’s chief executive, said the firm’s collapse was a “matter of profound regret”.
Fankhauser said: “Despite huge efforts over a number of months and further intense negotiations in recent days we have not been able to secure a deal to save our business.”
He added: “It has been my privilege to lead Thomas Cook. It is deeply distressing to me that it has not been possible to save one of the most-loved brands in travel.”