Waitrose is one of almost 900 brands that will have to prove they still count the royal family among their customers if they don't want to change their logo.
One of the most famous examples of this is the classic Heinz tomato ketchup, which for years has borne the royal seal as proof that their ketchup is fit for royalty.
However, when the monarch dies all of these warrants become void and will only be reapplied if they can prove they keep supplying the family now that Charles is King.
Nearly 900 brands are facing having to prove they still supply the royal family or wiping that royal seal of approval off their branding, and Waitrose is one of the biggest names on the list.
This branding armageddon isn't imminent given that they've got up to two years to prove they still sell to the Windsors before they've got to change the designs, but that clock is ticking.
Warrants can't just be granted for the occasional sale, businesses also have to prove they've been supplying the Royal Family on a regular basis for at least five out of the last seven years.
Between 20 and 40 Royal Warrants are granted each year, and around the same number get cancelled.
In addition to the royal seal on products which are granted warrants, they also say which member of the family likes using that particular product.
For example, products which bore the phrase 'By Appointment to Her Majesty the Queen' were ones granted a warrant for supplying the Queen herself.
At least in the case of Waitrose, they should be alright considering the supermarket shelves stock produce from a partnership with King Charles III.
The Waitrose Duchy Organic brand is produce that's come from a partnership between the supermarket and a company set up by the then Prince Charles.
Members of the Royal Family have been spotted in the supermarket from time to time, so they probably have very little to fear when it comes to losing their Royal Warrant.
The same can't be said for the almost 900 other businesses on the list, they'd better hope King Charles III likes whatever it is they have to sell.
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