HMS Diadem (84): From Covering the Tirpitz Raids to Pakistan's Flagship

Built on the Tyne

HMS Diadem was built by Hawthorn Leslie and Company at Hebburn-on-Tyne, her keel laid on 15 December 1939, launched on 26 August 1942 and completed on 6 January 1944, a Dido-class light cruiser of the Bellona subgroup, a modified design carrying four turrets and strengthened anti-aircraft armament that reflected hard-won lessons from the early years of the war.

The lesson in question was that the Dido class had not quite worked. They had been built around the 5.25-inch dual-purpose gun, a weapon chosen on a very specific calculation: it was reckoned to be the heaviest shell a gun crew could go on lifting by hand. In practice the gunhouses were cramped, the shells and cartridge cases were a struggle, and the guns managed about seven and a half rounds a minute sustained, which is respectable for a surface action and nowhere near enough against aircraft. The mountings also elevated and trained too slowly to follow anything fast. A ship built as a fleet anti-aircraft cruiser was, in her original form, not very good at it.

What the Bellona subgroup did about it was mostly a matter of weight. Dropping a turret and lowering the bridge by a whole deck took enough topweight out of the design to allow full radar control to be fitted to the 5.25-inch turrets and the pom-poms, and that is what actually fixed the problem: the gun was still slow, but a radar-directed slow gun that knows exactly where the aircraft is beats a fast one being aimed by eye. Diadem and her sisters are the point at which the British anti-aircraft cruiser finally started working, and it happened in 1943, which is late.

She displaced 5,950 tons standard, or 7,200 tons fully loaded, could make 32.25 knots, and carried a crew of around 530, her eight 5.25-inch dual-purpose guns supplemented by pom-poms, 20mm cannon and torpedo tubes.

Covering the Tirpitz Raids

Diadem's war began with Arctic convoy duty, and on 3 April 1944 she formed part of the covering force for Operation Tungsten, the Fleet Air Arm's carrier strike against the German battleship Tirpitz in Kaafjord, flying the flag of Rear Admiral F. H. G. Dalrymple-Hamilton. Fifteen bombs struck Tirpitz that day, killing 122 of her crew and wounding 316 more, though not enough to sink or fully disable a ship that would go on tying down a disproportionate share of Allied naval resources simply by existing for another eight months.

The scale of the effort spent on that one ship is the real story of the northern war. Tirpitz never sank a single Allied merchant vessel. She did not need to: as long as she existed in a Norwegian fjord, the Admiralty had to keep a battle squadron in home waters against the day she came out, and it was the mere possibility of her sailing that caused convoy PQ17 to be scattered and destroyed in 1942. The Royal Navy attacked her with midget submarines in September 1943, an operation that earned Godfrey Place his Victoria Cross and is set out in the article on HMS Corunna, whose captain he later became. Then came the carrier strikes that Diadem covered. Then a further six of them through 1944. In the end it took Lancasters and twelve-thousand-pound Tallboy bombs, in November 1944, to turn her over. Diadem was part of a campaign that ran for three years against a ship that mostly sat still.

D-Day and the Brittany Coast

Diadem crossed the Channel on the night of 5 and 6 June 1944 as part of Force G, opening fire on the Moulineaux battery near Bény-sur-Mer and on German strongpoints held by the 1716th Artillery Regiment as troops stormed ashore at Juno Beach, and surviving an early collision with a Rhino ferry without being put out of action. She spent the rest of June supporting ground forces around Caen, before moving on to offensive patrols off the Brittany coast. On 12 August 1944, she and accompanying destroyers sank the German auxiliary Sperrbrecher 7, a useful and satisfying piece of coastal interdiction work in the weeks following the landings.

A Brush With German Destroyers

From September 1944, Diadem returned to covering Russian convoys and carrier raids along the Norwegian coast, and on the night of 27 and 28 January 1945 found herself engaging three Narvik-class destroyers of the German 4th Destroyer Flotilla, Z31, Z34 and Z38, as they tried to slip from northern Norway to the Baltic. Alongside HMS Mauritius, Diadem hit Z31 hard enough to wreck her forward turret and start a fire that killed fifty-five of her crew and wounded twenty-four more, with Z34 taking lighter damage, though the faster German ships ultimately outran their pursuers and escaped, in what proved to be one of the last surface actions the Kriegsmarine ever fought, a remarkably dramatic reminder that gun-on-gun naval combat had not entirely given way to aircraft and submarines even in the war's final months.

Postwar Service and Reserve

After the war, Diadem remained with the 10th Cruiser Squadron and served on with the Home Fleet until 1950, before spending the following six years in reserve, part of the large surplus of wartime cruisers for which peacetime Britain had steadily less use.

A Long Second Life as PNS Babur

Diadem's sale to Pakistan was announced on 29 February 1956, and after a refit at Portsmouth she was formally handed over on 5 July 1957, entering Pakistani service as PNS Babur.

Her most notable moment under the new flag came on the night of 7 and 8 September 1965, when she led a task force of six destroyers and the submarine PNS Ghazi in a short bombardment of the Indian coastal town of Dwarka, aimed partly at a suspected radar installation. The four-minute barrage relied heavily on ammunition inherited from before Partition, and most of the fifty shells fired failed to explode; Indian accounts afterwards recorded little more damage than a single unlucky hit on an empty railway waiting room, and no casualties on either side, a genuinely low-key outcome for what has since become one of the more argued-over episodes of the whole war.

One of the destroyers behind her that night had a familiar hull. PNS Alamgir, third in the line, had been HMS Creole, a British C-class destroyer completed too late for the Second World War and sold to Pakistan in 1958; her story is set out in the article on HMS Creole. Two ships built on British slipways for a war against Germany, firing pre-Partition British ammunition at an Indian fishing town in 1965, most of which failed to go off.

During the 1971 conflict, she served as headquarters ship on patrol some seventy miles west of Karachi, helping protect the port and its oil tankers rather than seeking out a fight of her own. By then she had already spent a decade as a cadet training vessel, a role dating back to 1961, before being renamed Jahangir in 1982 and finally broken up in 1985, bringing to a close more than four decades of service under two flags.

The other four ships of her subgroup went four different ways, which for a group completed within a year of each other is quite a spread. Spartan was the only one lost: on 29 January 1944, a week into the Anzio landings, she was hit by a Henschel Hs 293, the radio-guided glide bomb, and sunk, which makes her one of the earliest warships in history destroyed by a guided missile. Bellona, Black Prince and Royalist all went to the Royal New Zealand Navy after the war, Royalist being rebuilt almost from the keel up and serving as the New Zealand flagship into the 1960s. Diadem alone went east to Pakistan.

So five anti-aircraft cruisers, ordered to the same drawings for the same war, ended up as follows: one sunk off Italy by a guided weapon nobody had believed in a year earlier, three flying the New Zealand ensign in the Pacific, and one shelling an Indian fishing town with British ammunition made before Partition, most of which did not go off. There is no designing for that.

That is a far more eventful sentence than it looks, because of what was going on around her. On the night of 4 December 1971 the Indian Navy sent three small missile boats of its 25th Squadron, Nipat, Nirghat and Veer, each carrying four Soviet-built Styx missiles, straight at Karachi. Nirghat put two into the destroyer PNS Khaibar, on patrol off the port; the second went into her number 2 boiler room and sank her. The Indian force went home without a casualty or a scratch, and India has kept 4 December as its Navy Day ever since. Khaibar had begun life as HMS Cadiz, and that night is set out in full in her own article.

Babur was seventy miles west of the same port while it happened. Two ships built on British slipways for a war against Germany, sold to Pakistan within a couple of years of one another in the 1950s, spent the night of 4 December 1971 at opposite ends of the same twenty minutes: one of them destroyed by a Soviet missile fired from a Soviet boat by a third navy, the other lying offshore as a headquarters ship with nothing whatever she could do about it. The gun cruiser had been made obsolete, comprehensively and in public, and Diadem was there to watch it happen.

And the submarine she had led into the Dwarka raid six years earlier was already gone by then. PNS Ghazi had been sent round to mine the approaches to Visakhapatnam and to find and sink the Indian carrier Vikrant, and the Indians used an elderly destroyer, INS Rajput, to give the impression that Vikrant was in harbour there. On the night of 3 and 4 December Rajput got a contact off the port and dropped depth charges. Two heavy explosions followed shortly after midnight, and Ghazi was lost with all ninety-three men aboard. India credits Rajput. Pakistan has always maintained it was an accident inside the boat, possibly involving her own mines. The wreck was formally identified off Visakhapatnam by an Indian Navy rescue submersible in February 2024, and the two countries still describe the same event differently.