Royal Navy sailors outside Buckingham Palace (Picture: Royal Navy).
Royal Navy sailors have begun guard duties at royal palaces for only the second time in their history.
The sailors have stepped in to help the British Army, as many of its Foot Guards battalions are busy on overseas operations or in training.
In total, 104 officers and ratings are taking part in guard duties at each of the royal palaces and the Tower of London, until 19 December.
The Royal Navy's stint started on Monday morning, as 35 sailors took over from 1st Battalion Grenadier Guards at Buckingham Palace.
Officer commanding the Royal Navy Guard, Lieutenant Commander Richard Dobson, said: "This will be an intense and memorable experience for all of us at the end of several weeks of ceremonial duties training, just eight or nine days of it specifically on palace guarding.
"The instructors from the guards could not have been better: for those eight or nine days they really put us through our paces and prepared us thoroughly for our 'Fit For Role' inspection last week, enabling us to mount guards today."
Lieutenant Commander Dobson volunteered to lead the contingent of sailors, and is believed to be the first sailor to become Captain of the Queen's Guard since Sir Walter Raleigh in 1587.
He said the duties "could be regarded as the pinnacle" of his Navy career, which began in the 1990s.
Away from the public eye, the sailors will spend their time tending to their uniform and rehearsing drills.
Royal Navy and Royal Marines musicians are also part of the duties, with one of the bands playing music whenever the sailors are mounting or dismounting the guard.
They will hand back guard duties to the Army on 19 December, when they march out of Windsor Castle.
The Senior Service sailors are from three of the five fighting arms - the Surface Fleet, Submarine Service and Fleet Air Arm.
The only other time they mounted guards was in 2017 - the Year of the Navy.