Queen Elizabeth has reportedly banned the Duke and Duchess of Sussex from using their Sussex Royal brand

A source told the Daily Mail newspaper: "'In many ways this is inevitable given their decision to step down, but it must surely come as a blow to the couple as they have invested everything into the Sussex Royal brand The Queen would have had little choice, however.

"The Sussexes' original plan - of being half-in, half-out working royals - was never going to work. Obviously, as the Queen has made clear, they are still much-loved members of her family.

"But if they aren't carrying out official duties and are now seeking other commercial opportunities, they simply cannot be allowed to market themselves as royals."

The Duke and Duchess - who are parents to nine-month-old son Archie - first launched their Sussex Royal brand in 2019, after opting to split their household from that of the Duke and Duchess of Cambridge.

Meanwhile, the royal couple recently axed 15 members of their UK staff.

The decision to close their office in Buckingham Palace came amid speculation that the Sussexes plan to spend the majority of their time in North America.

A source said earlier this month: "Given their decision to step back, an office at Buckingham Palace is no longer needed.

"While the details are still being finalised and efforts are being made to redeploy people within the royal household, unfortunately there will be some redundancies."