Henry Blagrove was born to Colonel Henry John Blagrove, CB of the 13th Hussars and Alice Evelyn Blagrove neé Boothby at Harbledown, Kent in April 1887. His family owned the Blagrove Estate in the Browns Town & Orange Valley of St Ann’s Jamaica. It had formerly been a slave plantation.
In 1901 aged 14 he entered naval service and trained at HMS Prince of Wales, joining HMS Good Hope as a midshipman in 1903 aged 17. Three years later Blagrove departed the ship as a sub-lieutenant and over the next three years earned promotion to full lieutenant aboard several ships, including HMS Sapphire, HMS Arab and HMS Invincible, the latter being the first of many appointments aboard capital ships.
Following promotion to lieutenant in 1909, Blagrove saw brief service aboard HMS Highflyer, HMS Fox and the battleship HMS Vengeance, before taking a course ashore at Dartmouth College, where the outbreak of the First World War found him. At the conclusion of his studies in October 1914, Blagrove received appointment aboard HMS Tiger, a newly completed ship in the 1st Battlecruiser Squadron under Admiral David Beatty. Tiger was commissioned only days before Blagrove joined her and due to recruitment shortages she had a poor crew made up by deserters from other ships.
Three months after joining Tiger Blagrove saw his first action, as Tiger joined her sister ships in the Battle of Dogger Bank. Tiger fired several hundred shells during the action, but her overall performance was poor, scoring few hits and suffering the loss of ten men to German counter fire. Nevertheless, Tiger was involved in the battle's final moments as the stricken German battle cruiser SMS Blücher heeled over and sank with nearly 800 lives. In late May 1916, a much improved Tiger became involved in the war's largest naval action, the Battle of Jutland. Tiger was engaged in the action from start to finish and despite the loss of three of her compatriots to German fire, Tiger escaped mortal damage, taking at least 15 hits and losing "Q" turret but only suffering 24 fatalities. The battle as a whole was a confusing affair without a clear victor but within 24 hours Tiger had recovered sufficiently from her damage to be able to return to active service, something few German ships could boast.
In November 1917, Blagrove was transferred to the HMS Queen Elizabeth, a fast battleship which had spent much of the war in the Mediterranean. Unlike the battlecruisers in Rosyth, Queen Elizabeth was stationed in Scapa Flow in the Orkney Islands and it was there that Blagrove met his future wife Edith Lowe, who was serving as a Wren. The couple would be married in 1921 and later have two daughters. Aboard Queen Elizabeth, Blagrove served out the war, being present at the surrender of the German High Seas Fleet and their subsequent scuttle in Scapa Flow. During the war he was promoted first to lieutenant-commander and later to full commander in 1919. Blagrove was also awarded the Italian Silver Medal for Valour in 1917. He departed Queen Elizabeth in 1920 and joined HMS President during which he saw staff appointments at Cambridge University and in the office of the Second Sea Lord.
In 1922, Blagrove joined HMS Excellent for a training course and then joined HMS Cardiff for his first posting aboard her, later being removed to HMS Ceres as her temporary captain for a month and then returned to Cardiff as her executive officer until January 1925. Further staff and training appointments followed, Blagrove being stationed at HMS Victory, HMS President and HMS Pembroke before being given command of HMS Curacoa in 1927 and promoted to captain. In 1932, after several staff appointments, Blagrove was briefly placed in command of HMS Norfolk and was then returned to shore duties at the Admiralty in 1934.
In 1937, Blagrove spent a year commanding HMS Sussex (96) and in 1938 was given the promotion to rear-admiral and placed on the staff of the Admiral Superintendent at Chatham Dockyard after a period as Naval Aide-de-Camp to King George VI. In January 1939 with war impending, Blagrove was given command of the 2nd Battle Squadron (United Kingdom), consisting of the battleships HMS Royal Oak and HMS Royal Sovereign stationed at Scapa Flow. Training and preparing his force in the run up to and opening weeks of the Second World War, Blagrove proved himself a capable and efficient officer, despite some doubts regarding his quiet personality and consequent suitability for service in a seagoing command.
HMS Royal Oak was sunk late on the night of 13 October 1939 after German submarine U-47 entered Scapa Flow by bypassing its blockship defences. Initially Kapitänleutnant Günther Prien, the commander of U-47, had been disappointed to find that the Royal Naval anchorage was largely empty; this was the result of a recent order from Admiral Charles Forbes to clear Scapa Flow in case of air attack. However Royal Oak was retained because she carried a large battery of anti-aircraft guns.
On sighting the battleship, Prien began his first attack run at 00:58hrs by firing three torpedoes. Only one caused a glancing blow on the bow of the Royal Oak. An alarm was raised aboard ship however it was mistakenly given for "danger of a potential internal explosion" not for a submarine attack. When no explosion seemed likely, most crew members returned to their bunks. At 01:13hrs Prien began his second run. This time all three torpedoes struck the Royal Oak amidships causing a huge explosion followed by a severe list to starboard. Prien used the ensuing confusion to escape from Scapa Flow.
As the crew scrambled to leave the stricken battleship, rescue boats set out from the shore as nearby ships responded. However the darkness, oil slick and low water temperature meant that many of those who did escape the ship drowned before they could be rescued. Royal Oak rolled over and sank 15 minutes after being hit.
A total of 833 crew were killed in the disaster, a further 386 were rescued. Rear-Admiral Blagrove was not among the survivors. His body was not recovered and the manner of his death is unknown. Blagrove's family became aware of the sinking from newspaper billboards in Edinburgh the following day but were not overly concerned for his safety. They were notified of his death 24 hours later.
Blagrove's name is included on the Portsmouth Naval Memorial as his remains were never recovered. His actual gravesite, the wreck of Royal Oak, is a protected war grave and a memorial to all the men who died aboard her stands in St. Magnus Cathedral on the Orkney Islands. The islanders themselves also maintain the memory of those lost on the battleship and an annual ceremony remembers them at the site of the wreck. Blagrove's widow later worked on the efforts to break the codes of the German Enigma machine at Bletchley Park, and his family have made several visits to the Islands to commemorate their father's memory.
Rear-Admiral Henry Blagrove was an efficient, able and popular officer whose service record contains few blemishes and many commendations. His untimely death ended a promising and successful career. One of his commanding officers, on recommending him for captain in 1927, indicated his character with the assessment:
Above average. An exceptionally good officer which has caused me to recommend him strongly for promotion. Very good powers of leadership - exhorts an excellent influence - is tactful & easy to deal with. Cheerful, energetic & frank personality. Physically fit – plays & is interested in all games. He has been a Rugger player of a high order & understands the game. Socially popular & much liked in the mess. He has extraordinary energy & organising capacity, and a brain capacity above the average. Recommended for further employment in a more responsible position.
Blagrove's wife was Edith Gordon Lowe, who was Scottish, from Edinburgh. Their daughter, Mary Alice Blagrove, married Royal Navy officer Peter Gerald Charles Dickens. Blagrove's great-grandson is actor Harry Lloyd.