Queen to be made vice admiral in recognition of her support of the Royal Navy

General Sir Gwyn Jenkins, First Sea Lord and Chief of Naval Staff, said the honorary role would “further enhance Her Majesty’s relationship with the service”.

The appointment will be formally made later when Camilla visits Devonport naval base where, as the sponsor of HMS Astute, she will join a ceremony marking the end of the submarine’s first commission.

The honorary role, which dates back to the mid-16th Century, will include the formal presentation of a burgee, or pennant, by Rear Admiral Andy Perks, head of the submarine service, recognising the Queen’s ongoing support for the Royal Navy.

The First Sea Lord said “… the honorary appointment reflects the high regard in which Her Majesty is held by all of us.”

Sir Gwyn, who is a Royal Marine, met Camilla on Tuesday when she was installed as an honorary freeman and liveryman of the Worshipful Company of Stationers and Newspaper Makers, an organisation associated with the Royal Marines.

He said during the City of London event: “We’re super proud of Her Majesty’s role with HMS Astute, as are the crew, it really matters a lot to us as a Navy and to them as a crew that it’s the Queen’s submarine.”

The Queen joked to him about not wanting to serve on a submarine and the head of the Royal Navy said afterwards: “I think we would all recognise that being a submariner is a very special skill set, you have to be really committed to the role and what you do for the country.

“It can be phenomenally rewarding, it’s an amazing sense of teamwork onboard, but it’s not for everyone.”

At Devonport, the Queen and the crew will celebrate the submarine’s achievements over the past 15 years – the longest first commission of any Royal Navy submarine in history.

The hunter-killer submarine will undergo a major overhaul at Devonport naval base to allow her to continue patrols safeguarding the UK’s interests for years to come.

Commander Christopher Bate, commanding officer of HMS Astute, said the crew took enormous pride in the Queen’s sponsorship of their submarine and support for all onboard since she formally named the vessel nearly 20 years ago.

He said: “Her Majesty the Queen has supported us from the very beginning, she has consistently shown a deep commitment to all aspects of our work.

“Her continued engagement with our activities and achievements over the years has meant a great deal to us.”