Abta estimates the coach and rail operator had almost 7,000 forward bookings protected by Abta, comprising approximately 16,000 passengers.

Diamond operated under the Diamond Holidays, Diamond Rail Holidays and The River Cruise Line brands, according to the CAA website.

Everyone booked on packages will get a refund on the money they have paid, in some cases this may be through their bank or credit card company and we will give them a letter, which will make any claim straightforward.

Customers who need more help can contact Abta’s claims team on 0203 758 8743.

A small number of customers with flight-based holidays will be protected through the Atol scheme and should contact the CAA.

Abta said in a statement: “This is clearly going to be very worrying for the thousands of holidaymakers who have booked with the company.

“Although unfortunately we have to confirm that their holidays are cancelled, the company’s non-flight based package holidays, such as coach or rail trips, are fully protected through Abta.

“These kind of trips formed the majority of the company’s business, and customers with one of these bookings are advised to go to abta.com where they can start the process of claiming a refund.”