The news that Catherine, Princess of Wales, still better known to many as Kate, is to be allowed to issue her own Royal Warrants, is a welcome sign she is recovering from her diagnosis for cancer and is back carrying out public duties.

Here we look at some of the people and businesses that are given these warrants and by which member of the royals.

Royal Warrants are always approved by the monarch and are awarded to people and companies that regularly supply goods or services to the royal household.

The King will have been approached, probably by William on behalf of his wife, to see if Catherine could also award warrants.

King Charles III has continued to issue warrants, which he has been entitled to do since he was Prince of Wales. He received permission to do so from his mother, Queen Elizabeth II (who bestowed a total of 686 warrants during her long reign) to bestow them in his own right.

He issued 159 warrants as Prince of Wales. However, the late Queen did not allow his then wife, Princess Diana, to award any warrants. Instead, she used to send hand-written notes in recognition of excellent service, which were equally cherished by the recipients. Princess Anne is not permitted to send warrants, even though she is, arguably, the hardest working member of the Royal Family

Queen Camilla is entitled to award warrants in her own name, which she has done since Charles ascended to the throne. The record for warrants granted is held by the late Queen Mother, while the late Duke of Edinburgh was comparatively frugal with his, handing out just 38 during his lifetime.

Many suppliers of goods and services to the Royal Family are holders of Royal Warrants, highly sought-after public certificates showing that the company has the King or another member of the Royal Family as a client or customer.

Currently, only three royals can issue warrants – the King, Queen Camilla and the Prince of Wales – so even though firms may supply every other member of the family, they are not allowed to display a Royal Warrant.

To become eligible for a warrant, a company must have supplied goods or services for a minimum of three years.

And they do not have to be major companies with household names such as Rolls-Royce or Fortnum & Mason. In the tiny town of Ballater, near Balmoral in Scotland, nearly every shop, butcher, baker, chemist, grocer and wine merchant proudly displays its Royal Warrant.

It is a similar story in the area around Sandringham, Norfolk, where the Royal Family spends Christmas each year, with shops and businesses displaying similar signs.

Those who are awarded a Royal Warrant are entitled to have a ‘By Appointment To…’ on their stationery and on their buildings.

For example, when Catherine awards her warrants, the recipients will be allowed to claim ‘By Royal Appointment to Catherine Princess of Wales.’ This will become a highly sought-after award.

Warrants expire when the royal who bestowed them dies or if the company goes out of business or changes hands.

A Royal Warrant of Appointment (the full title) is awarded to tradesmen after they have applied to the Lord Chamberlain’s Office in writing once they have fulfilled the necessary qualifying period.

The Royal Household Tradesmen’s Warrants Committee then carefully considers the application. The new warrant holders are nominated each December, with the full list published in the London Gazette.

The Royal Warrants are coveted not only for the prestige they bring to the holder but also for the commercial advantages, as many customers like to buy their goods from companies that supply the Royal Family on the basis that, ‘if it’s good enough for royalty, it’s good enough for them’.

The warrant allows the person or company granted the privilege to use the legend ‘By Appointment’ and to display the Royal Coat of Arms on their products and also on their premises and delivery vehicles.

Royal Warrant holders are justly proud of their status and, once a year, members of the Royal Warrant Holders Association hold their annual banquet at Grosvenor House Hotel in London’s Park Lane.

Following the death of the royal who bestowed the warrant, recipients may continue to use them and enjoy the prestige they bestow for another two years. After that, if they hope to maintain the award, they need to apply again.

Also it is possible for a Royal Warrant holder to be stripped of the honour.

Among some of the more distinguished names to recently lose their warrant is chocolate maker Cadbury, at one time a personal favourite of His Majesty.

The company may not have committed any offence but the fact that they have fallen out of favour is enough to remove them from the list.