Booking.com has told The Independent: “As an extension of our overarching aim to provide our customers with transparent information about the total price they will need to pay at a property when they make a booking and to create a level playing field for all of our accommodation partners, we are updating our process when it comes to charging commission on mandatory extra fees that customers are asked to pay at the property.”

By keeping the basic rate low, hotels look more appealing on price-comparison sites, and also reduce the amount of commission paid to intermediaries. Resort fees are most widespread in Las Vegas and New York City, with many properties in California and Florida also adding charges.