Fleetway Travel has gone into administration, after 45 years of business.
The firm has offices in London and Sheffield, and employs around 85 staff members.
6,500 Atol-protected bookings will be refunded to holidaymakers who had booked trips with the company.
According to the CAA, none of the travellers are aboard at this time, The Mirror reports.
Andy Cohen, head of Atol, said: “We understand this will be concerning news for anyone who has booked to travel with the company or has had their booking cancelled. It is a sad day for the industry when a long-established business like Fleetway ceases trading.
“However, the Atol scheme exists for exactly this kind of situation and we are making arrangements so all Atol protected customers may make a claim.”
Stuart Jackson, chief executive of Fleetway, said: “It is with immense sadness that, despite our best efforts, we have been unable to overcome the tremendous hurdles placed in front of us.
“We have worked tirelessly to find solutions to save the company and jobs for our loyal employees that have served our 60,000 customers annually.
“However, it is immensely disappointing that the required funding or investment could not be secured to get us through this unprecedented crisis and save Fleetway Travel.”
Fleetway Travel has previously traded under the names of Exclusive Luxury Breaks, Explorer’s Collection, Late Bargains, Luxury Holiday Collection, Phone & Fly, Sail Away, Silversurfers Holidays and Travelsmart.