Triggering the UK’s biggest repatriation since World War II to bring back stranded passengers, British travel group Thomas Cook on Monday declared bankruptcy after failing to reach a last-ditch rescue deal.

The 178-year-old operator had been desperately seeking £200 million ($250 million, 227 million euros) from private investors to save it from collapse.

“Despite considerable efforts, those discussions have not resulted in agreement between the company’s stakeholders and proposed new money providers,” Thomas Cook said in a statement. “The company’s board has therefore concluded that it had no choice but to take steps to enter into compulsory liquidation with immediate effect.”

The government said it had hired planes to fly home an estimated 150,000 tourists to the UK, in an operation starting on Monday.

“Following the collapse of Thomas Cook and the cancellation of all its flights, Transport Secretary Grant Shapps has announced that the government and UK Civil Aviation Authority has hired dozens of charter planes to fly customers home free of charge,” a separate statement said, describing it as the largest repatriation in peacetime history.

“All customers currently abroad with Thomas Cook who are booked to return to the UK over the next two weeks will be brought home as close as possible to their booked return date.”

Thomas Cook chief executive Peter Fankhauser called it a “deeply sad day.”

“It is a matter of profound regret to me and the rest of the board that we were not successful,” he said.

“This marks a deeply sad day for the company which pioneered package holidays and made travel possible for millions of people around the world,” he added in the group’s statement

The latest development marks the end of one of Britain’s oldest companies that started in 1841 running local rail excursions before it survived two world wars to pioneer package holidays first in Europe and then further afield.

The firm now runs hotels, resorts and airlines for 19 million people a year in 16 countries. It currently has 600,000 people abroad, forcing governments and insurance companies to coordinate a huge rescue operation.

Thomas Cook has been hit by online competition, crippled by its 1.7 billion pounds of debt, a changing travel market and geopolitical events that can upend its summer season. Last year’s European heatwave, a symptom of climate change, also hit the British company as customers put off last minute bookings.

(With inputs from agencies)