From HP sauce to Burberry, the future of the Queen's endorsements is up in the air

Around the world, the kitchens, bedrooms and bathrooms of the population have something in common with many of the United Kingdom's royal palaces.

They are often stocked with the same items personally selected by Her Majesty The Queen and other members of the Royal Family, marked by what's known as a royal warrant.

Popular products such as HP Sauce, Kellogg's Corn Flakes, Burberry clothing, Clarins skin care or Elizabeth Arden cosmetics can all display a royal coat of arms, marking them as a product chosen by Her Majesty.

But those seals of approval may evaporate following the Queen's death this month, leaving some brands wondering if they'll continue to enjoy the favour of royal households as His Majesty King Charles takes the throne.

"There is incredible loyalty associated with with the royal coat of arms," said Feizal Chatur, CEO of Araam Inc. in Edmonton.

Chatur's company is the Canadian manufacturer of Hypnos mattresses, one of more than 700 brands that currently hold a royal warrant.

That means the brand carries the stamp of approval from Queen Elizabeth, and the company can display signage indicating that "By Appointment to HM The Queen," Hypnos products are official royal bedding and upholstery manufacturers.

Essentially, it's the mattress of choice for generations of Royals at many of their palaces, including Buckingham and Kensington Palaces, as well as Windsor and Balmoral Castles.

The implied endorsement the royal warrant provides means significant prestige, according to the Canadian branch of the mattress company.

"If it's good enough for the late Queen, then it's definitely good enough for a consumer," said Chatur in an interview with CBC Radio's The Cost of Living. Both Queen Elizabeth and the Queen Mother issued royal warrants for Hypnos mattresses, according to Chatur.

Royal warrants have been granted by the Royal Family since the 15th century, with royal coats of arms being displayed by businesses since the 18th. 

It's a history that makes the British Royals, by some measure, the original influencers before there were telephones, let alone the internet and Instagram.

"Over the years, the royal warrants have become, if you like, a … mark for quality of service and product," said Paul Alger, director of international affairs at the U.K. Fashion and Textile Association.

"It's a recognition factor that the Royal Family is bestowing on these great British brands."