Heinz, Waitrose, and hundreds of other brands' Royal Warrants became void after the Queen died. Now, they have to prove the royal family uses their products to get them back under King Charles III.

• Hundreds of brands had a Royal Warrant to use the royal coat of arms on their products, but it became void after the Queen died.
• The brands, including Waitrose and Heinz, can keep using the royal coat of arms for another two years.

Food manufacturer Heinz and British supermarket Waitrose are among the hundreds of brands that are going to have to prove the royal family still uses their products to continue using the royal coat of arms.

There are approximately 850 Royal Warrants held by about 750 companies or individuals, according to The Royal Warrant Holders Association, which also noted that that number changes frequently.

The late Queen Elizabeth II granted over 600 Royal Warrants that became void after her death in September.

However, the brand can continue using the royal coat of arms for up to two years if "there is no significant change within the company concerned," the association's website says.

A spokesperson for Waitrose told Insider that the company "will liaise with The Royal Household on future arrangements when the time is right to do so."

As the new reigning sovereign, King Charles III will have the power to review and grant the Royal Warrants.

Brands are able to use the royal coat of arms in their product design if they have a Royal Warrant of Appointment — a document allowing the brands to use coat if they supply goods or services to the royal family. According to the association's website, to qualify to apply for the Royal Warrant, companies and businesses have to supply "products or services on a regular and on-going basis to the Royal Households of Grantor/s for not less than five years out of the past seven."

Brands applying for the warrant also have to show they have policies and action plans around the environment and sustainability.

The royal coat of arms, which features the English lion on the left and the Scottish unicorn on the right holding a shield with emblems from the different parts of the United Kingdom, is accompanied by the Legend which is a statement at the bottom of the crest that says which member of the royal family granted the warrant.

The Royal Warrant is granted for up to five years and can be reviewed for renewal the year before it expires. According to the association, between 20 and 40 warrants are granted, and a similar number are canceled, each year.