Hundreds of thousands of holidaymakers were stranded on Monday after the collapse of the world's oldest travel firm Thomas Cook, sparking the largest peacetime repatriation effort in British history.

Running hotels, resorts and airlines for 19 million people a year, it has around 600,000 people abroad and will need the help of governments and insurance firms to bring them home.

As well as its 21,000 employees, the company's fall hit global booking websites, credit card companies, travel firms using its airlines, and British high streets where its travel agencies were forced to shut.

Tour operators like Thomas Cook have been struggling for years due to the rise of budget airlines and cheap online competition. In addition, Thomas Cook built up a 2.1 billion U.S.-dollar debt pile over a series of ill-fated deals. It had to sell three million holidays a year just to cover interest payments.

The company had agreed one a 900-million-pound (653 million U.S. dollars) rescue package with its banks and largest shareholder, China's Fosun, but lenders asked for an additional 200 million pounds to keep it operating through the winter.

In desperate meetings over the weekend, it failed to secure more funds, with the British government also refusing a bailout, judging it was not a good long-term bet.

Second largest shareholder Neset Kockar, a Turkish businessman, said the company would now be sold as a whole or in parts.

Emergency flights

British Prime Minister Boris Johnson pledged to get stranded British travelers home, another headache for his government as it tries to negotiate a fiendishly complicated withdrawal from the European Union.

The UK's Civil Aviation Authority (CAA) said it had a fleet of planes ready to bring home the more than 150,000 British customers over the next two weeks.

Thomas Cook's German airline subsidiary, Condor, said there were 240,000 people booked on its flights awaiting a return home. Its flights are still operating for now, and it has asked the German government for a bridging loan. In Germany, insurance companies will coordinate any repatriation.

There are around 50,000 holidaymakers affected in Greece, and around 35,000 from Nordic countries using Thomas Cook.

The collapse could provide a boost, however, to major rival TUI, whose shares surged more than 10 percent on Monday, and also Europe's overcrowded airline sector.

(With input from Reuters)