HMS Diana (D126): Sailed Close to a Nuclear Blast, Then Sank a Ship With Guns Alone

Constructed at Clydebank

HMS Diana was built by Yarrow and Company at Clydebank, yard number 1846, her keel laid on 3 April 1947, launched on 8 May 1952 by Lady McGrigor, and commissioned on 29 March 1954, a Daring-class destroyer that would go on to take part in two of the most historically distinctive episodes of any ship in this entire list. She very nearly went to sea under a different name altogether, having been earmarked during construction as HMS Druid before the Admiralty settled on Diana instead, a rare case of a warship's identity being decided only after her keel was already down.

At 390 feet long and 3,610 tons standard displacement, with a peacetime complement of around 297 officers and men and a top speed of over 30 knots, Diana was built for exactly the kind of long range, self-sufficient operations her Daring-class design had been drawn up for during the Pacific war, replenishment at sea included, even though the conflict those operations were meant to be fought in had already ended by the time she reached the fleet.

What the Daring class was, and why the Admiralty spent a while refusing to call these ships destroyers at all, is set out in the article on HMS Dainty. Diana was one of the four wired for alternating current, which is one reason she and Decoy were the two Peru eventually bought.

Gathering Data From a Nuclear Blast

HMS Diana was assigned to Task Group 308.4 during Operation Mosaic, the British nuclear weapons test programme conducted near the Monte Bello Islands off Western Australia in 1956, tasked with carrying out scientific measurements and collecting radiological data from the detonations themselves.

For the first test, codenamed G1, detonated on 16 May 1956 with a yield of between 15 and 20 kilotons, HMS Diana was positioned approximately 9.7 kilometres, roughly six miles, from ground zero on Trimouille Island.

Following the blast, she was decontaminated and sailed for Singapore on 18 May, direct and deliberate exposure to a live nuclear test environment of a kind that would be almost unimaginable by later safety standards.

She was back off the Montebellos for the second detonation, codenamed G2, on 19 June 1956, a device with a yield the Ministry of Defence would not confirm publicly, at around 98 kilotons, until 1985, several times larger than the one she had already sailed close to a month before. The scientific staff who had been embarked for G1 were notably absent for G2, a detail nuclear test veterans and their advocates have since pointed to as evidence that the risks were already better understood by the people making the decisions than by the roughly 300 men, including about 20 National Servicemen, spread between Diana's forward citadel and after compartment.

A technical report on the trial, numbered 4646R, later recorded that fallout could and did enter the intakes of her boilers and running ventilation systems in large quantities, that the resulting contamination was mainly loose and easily transferred to the lungs and stomach, and that proper decontamination of her machinery spaces was, in the report's own words, impracticable. Diana was for a time barred from entering Fremantle Harbour because of the radioactivity readings still being taken from her hull.

It is worth understanding what the Navy thought it was doing, because the theory was not careless and the practice was. Through the early 1950s the Royal Navy had been working out how to survive fallout, and the answer it arrived at was the sealed citadel: shut the ship up, keep the crew inside a gas-tight compartment on filtered air, and continuously spray the entire outside of the ship with sea water so that nothing radioactive could settle and stick. HMS Cumberland had been trialling exactly that pre-wetting system in the Mediterranean in September 1955, eight months before Diana went to the Montebellos, and it is the reason her people were in the forward citadel and the after compartment rather than on deck.

What Report 4646R records is that the theory held for the outside of the ship and failed completely for the inside, for a reason nobody appears to have thought through. A steam warship has to breathe. Her boilers draw air, in enormous quantities, through intakes that cannot be closed while the machinery is running, and so does the ventilation system that keeps the machinery spaces habitable. So the fallout went in, and, in the report's own finding, very little of it came out again. The men in the sealed citadel were being protected by a ship that was quietly filling up with the thing they were sealed against. Her official designation for the operation was Fallout Observation Ship, and the stated purpose of the exercise, set out at the time, was to learn the effects of fallout on the ship and on her crew.

Decades on, surviving members of Diana's ship's company have spoken of an alarming incidence of cancer, skin complaints, early cataracts and birth defects among their children, and by 2008 fewer than 60 of the roughly 300 men originally aboard were reported still to be alive. Successive governments have not accepted legal liability for these illnesses, even as research cited by nuclear test veteran campaigners found they were three times more likely than the general population to carry damaged chromosomes, and the argument over recognition and compensation for crews like Diana's continues to this day.

One part of that argument has since been settled, and it took seventy years. In November 2022 the government instituted the Nuclear Test Medal, covering everybody who took part in Britain's nuclear testing programme: service personnel, civilian staff, and the Australian, New Zealand, Fijian and Gilbertese people who were also there. Anyone who was aboard Diana off the Montebellos in 1956 is entitled to it, as set out in the article on HMS Cook, which was present at Operation Grapple the following year. Recognition, then, has come. Liability has not: no government has accepted that the illnesses were caused by the tests, and the great majority of the three hundred men who took Diana into that cloud did not live long enough to be given the medal.

Sinking the Domiat

HMS Diana's other defining moment came during the 1956 Suez Crisis. In the small hours of 31 October 1956, at the southern end of the Suez Canal, the cruiser HMS Newfoundland challenged the Egyptian frigate Domiat and ordered her to heave to. Domiat refused and opened fire with her 4-inch guns instead, killing one of Newfoundland's crew and wounding five. Newfoundland and Diana returned fire together and sank her.

Of Domiat's own company, 38 men were killed, and 69 survivors were pulled from the water by the two British ships. The action is sometimes cited as the last occasion on which one warship sank another purely through naval gunfire, without the assistance of missiles, torpedoes or aircraft, a notable historical distinction and a reminder that HMS Diana's career bridged two very different eras of naval warfare, the atomic and the resolutely traditional, within the space of just a few months, and a curiously old-fashioned way to settle an argument in what was otherwise a thoroughly modern war.

The other British ship in that action went the same way as Diana in the end, which is the sort of coincidence nobody would put in a novel. HMS Newfoundland, the cruiser who challenged Domiat and took the first casualties, was sold to Peru on 30 December 1959, three years and two months after the night at the southern end of the canal, and commissioned into the Peruvian Navy the following January as BAP Almirante Grau.

So both of the ships that sank the Egyptian frigate ended up in the same South American fleet, and for a decade they served in it together. There is a further twist in the timing. In 1973, the very year Diana was commissioned into Peruvian service as BAP Palacios after her refit at Birkenhead, Peru bought the Dutch cruiser De Ruyter and gave her the Almirante Grau name, so the old Newfoundland was renamed BAP Capitán Quiñones in May of that year to make room. She was hulked at Callao as a static training ship in 1979, decommissioned in 1980 and broken up.

Which means the last gun action in which one warship sank another without missiles, torpedoes or aircraft was fought by two ships that both finished their careers under the Peruvian ensign, one of them still firing Exocets thirty-seven years later. Domiat, meanwhile, had been HMS Nith, a River-class frigate that escorted the Normandy landings before being transferred to Egypt in 1948, so all three of the ships that fought that night had been built in Britain and all three had at one time worn the White Ensign.

Search and Rescue

In January 1968, HMS Diana took part in the search for the missing Israeli submarine Dakar, lost with all hands in the Mediterranean, and assisted the burning Spanish tanker MV Bahia Blanca, further variety in a career that had already ranged from nuclear science to gunnery combat.

A New Life as BAP Palacios

The Peruvian Navy acquired HMS Diana in 1969 alongside her sister ship HMS Decoy, renaming her BAP Palacios with hull number DM-73 in honour of Enrique Palacios, who died fighting at the Battle of Angamos during the War of the Pacific in 1879 (Decoy, for her part, became BAP Ferré, DM-74).

The transformation was more than cosmetic. During a major refit at Cammell Laird in Birkenhead between 1970 and 1973, her foremast was rebuilt to carry a Plessey AWS-1 air search radar and eight Exocet MM-38 anti-ship missiles were fitted forward, in place of the close range gun director she had carried as Diana, before she was commissioned into Peruvian service in April 1973. A further refit at the SIMA dockyard in Callao in 1975 and 1976 removed her Squid anti-submarine mortar and added a helicopter landing deck, upgrades that would have looked entirely unfamiliar to the sailors who had taken her through a nuclear test and a gun battle two decades earlier. She remained in service until finally being stricken in 1993, closing out a notably extraordinary near four-decade career that had taken her from the radioactive aftermath of a British nuclear test to more than two further decades of active naval duty on the other side of the world.