The Duke of Edinburgh has for the first time given a detailed account of his involvement in a dramatic Second World War naval battle which earned him a military honour.
Philip, 90, has described his part in the Battle of Cape Matapan, where British warships destroyed Italian vessels in waters off the coast of Greece in 1941.
The Duke was mentioned in dispatches for operating a battleship's search light during the decisive naval encounter and picking out enemy targets.
The Italian fleet had been caught unawares by British warships who sunk three cruisers and two destroyers.
Philip's description of events comes in the foreword to Dark Seas: The Battle of Cape Matapan, the first in a series of books about some of the great naval actions and campaigns of the 1939-45 war.
The Duke had joined the Royal Navy as a 17-year-old cadet in the spring of 1939 as the storm clouds of war gathered on the horizon.
Two years later he was a midshipman serving on a battleship from WWI, HMS Valiant, during the battle, and described his rank as the "lowest form of life in the Navy".
In what may be a joke, he says "all these events took place 70 years ago, and, as most elderly people have discovered, memories tend to fade", so his eyewitness account needs to be treated as "faction".
But the royal seems very clear about his crucial involvement in the battle picking out two enemy warships in the darkness.
He says: "I seem to remember that I reported that I had a target in sight, and was ordered to 'open shutter'. The beam lit up a stationary cruiser, but we were so close by then that the beam only lit up half the ship.
"At this point all hell broke loose, as all our eight 15-inch guns, plus those of the flagship and Barham's started firing at the stationary cruiser, which disappeared in an explosion and a cloud of smoke.
"I was then ordered to 'train left' and lit up another Italian cruiser, which was given the same treatment."
The Duke said: "The next morning the battle fleet returned to the scene of the battle, while attempts were made to pick up survivors. This was rudely interrupted by an attack by German bombers."
He concluded: "The return to Alexandria was uneventful, and the peace and quiet was much appreciated."
The Italian fleet had been caught unawares by British warships who sunk three cruisers and two destroyers for the loss of only one aircraft.
During his naval career the Duke rose through the ranks, becoming, when 21, one of the youngest officers in the navy to be made First Lieutenant and second-in-command of a ship.
After the war, he was promoted to Lieutenant-Commander and was given command of the frigate HMS Magpie and was known as "Dukey" by his men.
By now he was married to the then Princess Elizabeth and his career came to an end a few years later when the King, George VI, died in 1952 and his wife became Queen.