Holiday booking firm Low Cost Holidays has gone into administration affecting 27,000 holidaymakers current in resorts and 110,000 with bookings.
Market turbulence surrounding the EU referendum result - including the fall in the value of the pound which dissuaded many customers from travelling - was blamed.
The company also pointed to the terror threat hitting the travel industry after a series of incidents - including the latest deadly attack in Nice. Big travel sector players including easyJet, Thomas Cook saw share price falls on Friday in the wake of the outrage.
In a statement, administrators Smith & Williamson said the majority of Lowcosttravelgroup staff had been made redundant, with a total of 451 laid off including 120 at Gatwick and 264 in Krakow and the rest in Majorca and Switzerland.
The Civil Aviation Authority said the company was not part of the ATOL scheme which protects customers who have booked holidays with the firm and advised them to check the status of their booking with airlines and hotels.
Administrators for the firm said the slump in sterling had played its part in its demise as it had put off Britons - 60% of its customers - from booking holidays.
They also said that uncertainty ahead of the referendum had caused some customers to delay holiday decisions.
The statement said flights for all of those currently in resorts had been paid for so those holidaymakers would be able to fly home.
However, the company said in a separate statement that some may be asked to pay locally for their hotels, transfers or car parking, to reclaim on travel insurance or from their credit card provider.
Meanwhile, administrators said that among those who had yet to travel "a small number will have problems as regards their flights not having been paid for" while "many will have problems" with hotel rooms not paid for.
Lowcosttravelgroup had a turnover of around £500m last year, administrators said.
It sold hotel accommodation through wholesale brand Lowcostbeds and direct to consumers through retail business Lowcostholidays. The company also sold holidays to consumers in Europe and Scandinavia.
Finbarr O'Connell of Smith & Williamson said: "The group experienced significant market headwinds in the run up to the EU referendum as holidaymakers delayed decisions.
"This was compounded by the Leave vote itself and the subsequent fall in value of the pound.
"Regrettably, in these extraordinary conditions, the directors had no option but to place Lowcosttravelgroup Limited into administration."