Princess Anne was praised by one of King Charles’s former butlers, who said she would have made an “amazing Queen”.

Grant Harrold, who worked for King Charles between 2004 and 2011, claimed that the Princess Royal, who celebrates her 74rth birthday today, will not be “slowing down anytime soon”, as the royal is set to step up her engagements even more in order to support her brother.

Speaking on behalf of Spin Genie, he said: “Princess Anne is one of the busiest royals.

“She used to do at least double the amount of engagements we see William and Kate doing, and maybe more than the King. This year will be just as busy for her.”

The former royal butler added: “It’s important to Anne to keep going. She finds it hard to step back or take a break.

“She has this hard-working ethic that comes from her late mother and father. She would have been an amazing Queen.”

Mr Harrold hailed King Charles’s older sister and said she is hard-working, yet “kind and courteous”.

He revealed that she is exactly the “same behind closed doors as she is in public”.

The former royal staffer explained: “Anne is hard-working, but very kind and courteous. She has her father’s sharp side.

“She always wanted to get things done but was always great fun.

“I often saw her having a great laugh with her father when they did the barbeques together. You could see how special their bond was.”

He added: “Anne is the same behind closed doors as she is in public. She is often out and about.

“You will see her getting her food at her local Waitrose or having a look around an antique shop.

“Anne is very hands-on and wants to live her life the way she wants to. She does her own thing and doesn’t always want anyone doing things for her. She likes to be in control.”