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"Operation Mosaic (excerpt), by Brian Marshall

Operation Mosaic took place at Monte Bello in May and June of 1956. It comprised the detonation of two Atomic Bombs which were part of the British programme to develop a nuclear capability that would place the United Kingdom on a par with any other nation in the world, so far as destructive potential was concerned.
The Monte Bello Islands lie off the North-West coast of Australia. Ideally situated for the purpose of nuclear testing, they are uninhabited and at the periphery of the seemingly limitless Southern Ocean where radioactive fallout, borne on the North-East wind, may be carried away for thousands of miles and do no harm to anyone. There are no islands to the west and south, and ships pass but rarely, all the way to where the Indian Ocean merges imperceptibly into the Antarctic. It is a part of the world unknown throughout history to all but a few intrepid voyagers.
The islands hardly qualify as islands at all, being little more than sandbars that are covered in scrubby vegetation and barely remaining above water at high tide. Among these unprepossessing banks in this remote archipelago are some with rather grand names, Trimouille and Alpha Island being the two with which the nuclear tests were directly concerned.
It was the Royal Navy that was most closely involved in the conduct of the tests and a group of warships gathered at the islands under the command of Commodore Hugh Martell who had his headquarters in the Tank Landing Ship, HMS Narvik. There were also a couple of destroyers from the Far East Fleet whose job it was to keep innocent merchant vessels away from the danger area, and also presumably, to ensure that unauthorised visitors and other interlopers did not get close enough to see anything the British authorities would not wish them to see.
Another British destroyer was also present for the whole of Operation Mosaic, a fast, sleek, and highly dangerous looking warship that was not concerned with either the technical aspects of the bombs, or the keeping away of unwelcome visitors, though she was well suited to the latter task. The ship was HMS Diana, a Daring Class destroyer detached from the Mediterranean Fleet to this ad hoc flotilla assembled at Monte Bello. Like her sister ships: Duchess, Decoy and Diamond, left behind in Malta, she was heavily armed with three twin 4.5 inch turrets, three twin 40 mm. anti-aircraft guns, ten 21 inch torpedo tubes and a three barrelled Squid anti-submarine mortar. All this armament of course required a lot of men, and Diana, though only of some 2,500 tons, had a ship's company of 300. By comparison with the new Daring Class destroyers of the twenty-first century, almost three times Diana's displacement, she was seriously overcrowded. Her role at Monte Bello was to be alarmingly different from that of the other ships assembled there.
Diana was just commencing her second commission, having been in dockyard hands at her home port of Devonport in 1955, and joined by her new crew less than three months before the scheduled date for Operation Mosaic. She had come from Plymouth by the shortest route: through the Mediterranean, the Suez Canal, Red Sea, Indian Ocean and down through the islands of the East Indies to Western Australia. Her first call along this journey to the other side of the world was at Gibraltar from where she proceeded to Malta and secured to a buoy in Grand Harbour, the place that in normal circumstances would have been her home for the next nine months or so.
She was not to be long in Malta, however. Diana's Captain, John Ronald Gower DSC., paid his customary call on the admiral in overall command of the destroyers and was officially detached to Monte Bello on 12 April. Diana was never to see the Mediterranean again, at least during her current commission. Her course took the ship through the Suez Canal and down the Red Sea to Aden, still an important staging post for British and other European ships making their way to and from India and the Far East. Next was Colombo, where the towering white hulls of P and O liners dwarfed Diana anchored nearby. Finally came Singapore, major base of the Royal Navy in South East Asia and melting pot of the races of the Empire. The last leg of this voyage was from Singapore, through the Indonesian islands and finally to Monte Bello. The distance covered was some 11,000 miles which had taken five weeks, including the various calls paid along the way. She had steamed at an average speed of around twenty knots. Diana and her crew were in very good shape.
It quickly became apparent to the ship's company that their Captain was a man of exceptional ability and character. Not one member of the ship's company had served with him previously and no reputation had preceded him, but in a very short time it was clear that here was a just and considerate man, a skilled and highly professional sea officer and an inspirational leader. John Gower's presence in command of Diana had come about through a remarkable turn of fate. He was an enthusiastic games player who in 1939 had started the qualifying course to become a specialist PT officer but had never completed it because of the impending war. He had, in his younger days, been a noted athlete at Inter-Service and County level, and had dared to hope for recognition at Olympic level. The games of 1940 did not take place of course, nor those of 1944, and his chance was gone for ever. His skills and interests were not forgotten by the Navy, however, and in 1954 he was appointed Director of Sports and Games for the Royal Navy and Superintendent of the Navy's School of Physical Training in Portsmouth. This was a job he relished and he looked forward to an extended tenure. When a Captain was appointed to command Diana on completion of her refit, it was not John Gower who was named. The name of the captain who was initially appointed remains unknown to the officers and ship's company he was meant to command. He was on leave before taking up his new appointment when he broke both his legs in a skiing accident and a replacement had to be found at once. The choice fell upon John Gower, which was seen as a blessing by the men who were to serve under him when later they learned that he had not been first choice.
Diana had been singled out by the Admiralty for a task unprecedented in the Royal Navy, or indeed any other navy. She was to take part in the testing of nuclear bombs, though her role lay not so much in the bombs themselves, but in the after effects of them.
The Second World War had been brought to a sudden and horrific end with the dropping of the Atomic bombs on the Japanese cities of Hiroshima and Nagasaki. These events had demonstrated before the eyes of the whole world the terrible power that man could, through his scientific ingenuity, release upon his enemies. Then, as international relations in the post-war period began to turn more fraught with tension and mistrust it quickly became apparent that it was not just the Americans who possessed 'The Bomb,' as it came to be called. So too did the USSR. This led inevitably to an escalation, not only in the number of nuclear weapons possessed by the potential adversaries, but in the very nature of them. The Atom Bomb, with all its proven destructive power, was now thought not big enough, nor sufficiently destructive; and so the ingenuity of scientists created an even more terrifying device: the Hydrogen Bomb. The explosive force of the A bomb was measured in thousands of tons of TNT, or 'kilotons;' that of the H bomb was calculated in millions of tons, or 'megatons.'
While this so-called nuclear arms race was going on between the USA and USSR: the superpowers, Britain did not remain idle. The United Kingdom still regarded herself as a major force in the World and was determined that she too would become a full nuclear power in her own right, rather than simply as an ally of the USA. The necessary skill and knowledge was abundantly present among scientists in Britain and it was not long before the first successful British test of a nuclear bomb took place. This was at the Monte Bello Islands on 3 October 1952.
By this time, however, production of the Hydrogen Bomb was already a reality and Britain, nuclear power though she now was, still lay far behind the USA and USSR. She was faced, therefore, with the question as to whether she too should develop and test the Hydrogen Bomb. Despite the close relationship between the two countries, the USA refused to pass on to Great Britain the necessary technology for the construction of the H Bomb because of security fears following the defection from Britain to the Soviet Union of the spies: Burgess, Philby and McLean, and so it was necessary for Britain to proceed independently. The decision to go ahead with production of the Hydrogen Bomb was taken by the Prime Minister, Winston Churchill, on 16 June 1954 and a process of development was set in train that would, less than two years later, indirectly involve HMS Diana. In order successfully to detonate a Hydrogen Bomb it was evidently necessary to have a nuclear trigger, and the development of such a trigger was the purpose of the tests held at Monte Bello in 1956. It led to Britain's first successful detonation of a Hydrogen Bomb at Christmas Island in 'Operation Grapple' on 15 May 1957,
Whatever tasks, whether concerning science or security, fell to the other ships at Monte Bello, Diana was not part of either function. She had been brought to the far side of the world at the behest of the Admiralty to provide the answer to a question that had taxed the Chiefs of Staff for some time. This was; 'In the event of a nuclear attack on the fleet, what would be the effect of the explosion and its ensuing radioactive fallout on: the ship, her contents, equipment and, above all, her crew?'
The report prepared by Diana's Medical Officer shortly after the tests is quite specific on the question of the ship's purpose at Monte Bello.
In general terms the ship's function was:
a) to observe the distribution of radio-active fallout material in an operational ship during and after the passage of the radio-active cloud;
b) to test the effectiveness of pre-wetting and all other established A.B.C. precautions and drills and to modify the latter as necessary in the interests of 100% efficiency;
also to test in practice the available radiac instrumentation.
c) to observe the effects on men and materials of a) and b);
d) to provide a platform for purely scientific observations.
The ship could not, of course, be exposed to the direct blast and heat of a major nuclear explosion; the outcome of such an eventuality was self-evident. The answer sought was in an area much more insidious than outright proximity to the explosion, and so the question to be addressed by Diana was: how would the ship, her weaponry, her machinery and equipment respond to exposure to the radioactive matter that might descend upon her in the aftermath of the explosion? Again the answer should have been fairly obvious. Radioactivity was not going to damage the ship. The plates and decks would not be affected by it. The engines would still run, the guns would still fire. Only the people were vulnerable. It was the crew that would, if exposed to radiation, suffer from it. But everyone knew that already. Everyone knew that human cells will be adversely affected by exposure to radiation and that long-term damage can ensue.
What the Admiralty had in mind was to see if a ship could be provided with the means of protecting her crew from the malign effects of radiation and thereby maintain her fighting efficiency. The only way to conduct such a test was for the ship to allow the radioactive matter from a nuclear explosion to land upon her as the mushroom cloud dispersed and the minute particles began to fall back to earth. Operation Mosaic provided the ideal opportunity. Here was a series of nuclear bomb tests already scheduled to take place. Why not simply send along a suitable ship and expose her to radiation under actual conditions of nuclear war? This would not be simply a drill; it would be the real thing, albeit using fallout produced by the British and not by some hypothetical enemy. In other words, when the detonation of the bomb was imminent and the attendant ships steamed away from the islands to a safe position upwind, Diana must steam instead to a position downwind where the dispersing cloud would bring the fallout down upon her.
The Chiefs of Staff did not know, they could not know, how safe the men would be. This was a question of trial and error. Could systems be devised by which members of the ship's company might protect themselves from radioactivity, and maintain the ship as an effective fighting unit of the fleet? This in itself is a perfectly valid question and one on which the Admiralty was quite entitled to ponder. The Admirals were right to ask whether or not a ship would still be capable of warlike operations. However, the implications of what they were ordering the ship and her crew to do, had clearly not been thought through. A ship exposed to radiation might well retain her fighting efficiency and give a good account of herself in action against an enemy for months after exposure. What, though, of the longer term effects? People exposed to radiation and damaged by it often betray no symptoms for years. The Admiralty's question might be answered perfectly satisfactorily in the short term only for members of the ship's company to have received doses of radiation the effects of which could remain undetected for half their lifetime. Equally, a man exposed to the fallout might suffer damage that would only manifest itself in his children, his grandchildren, or even his great-grandchildren.
Diana arrived at Monte Bello in early May and anchored a little way off shore in the 'parting pool' as her draft did not allow her to enter the lagoon within the island group. Captain Gower paid the customary visit to the Commodore in HMS Narvik who sent a group of scientists over to Diana to examine the progress made in the ship in preparation for her forthcoming task. They reported as follows:
"General impression was everyone understood the basic problems and how
to tackle them but they have fallen short in the apparatus and tools to do
the job."
We might speculate here as to who 'they' could be. Did the scientists mean, the Government, the Admiralty, or did they mean the officers and ship's company of HMS Diana? It could hardly mean the Dianas, since they were totally unschooled in such matters. Whoever had 'fallen short,' in the provision of apparatus and tools it was someone much further up the chain of command than Captain Gower and his men.
The scientists went on to declare:
"We cannot, however, assume any direct responsibility for the radiological
safety of Diana since this is outside our terms of reference."

This is a point of great interest which Captain Gower was later to refer to as 'the usual disclaimer.' A critical question is raised. It is clear that the experts were concerned for the men's radiological safety, otherwise there would have been no point in raising it as a separate issue. If the scientists on the spot were concerned for Diana's radiological safety but refusing to take any responsibility for it, then who was responsible for the well-being of these 300 men? Were the Government and the Admiralty back in London holding themselves accountable for the health of the crew, or were the Dianas themselves supposed to be responsible? What was the official position on this matter, before the bombs were detonated?
There was some reason for a delay in detonating the first bomb and so Commodore Martell allowed Captain Gower to take his ship down to Fremantle for a short break in that pleasant port, and Perth: its much larger neighbour. The trip south proved quite eventful as it involved the worst weather many of the crew had ever experienced. Despite their warlike appearance coupled with a certain grace and beauty of line, the Daring class were somewhat top-heavy, their high superstructure and large gun turrets causing this class of ship to behave quite badly in a heavy sea.
The ship's company was graciously entertained in Western Australia, and after four days set out to return to Monte Bello, looking forward to a return visit when the first nuclear test was completed. This was never to be, however. The Australian authorities declared Diana to be contaminated by radioactive fallout and would not allow her to enter any port in the country.
Diana returned to Monte Bello on 14 May and Mosaic I, the detonation of the first bomb, took place on the 16th. Forbidden the hoped for return to Fremantle, and clearly unable to go back to Monte Bello for the time being, she turned north and headed for Singapore, there to spend a few days of both work and recreation.
After a short but welcome stay in Singapore the matter of her return¬ to Monte Bello became pressing and she arrived back at the islands on 7 June. Mosaic II did not take place until 19 June and the ship's company was obliged to occupy itself as the ship rode at anchor in that desolate, ravaged, and radioactive place. The men needed to be kept interested; morale had to be maintained. This was something at which Captain Gower excelled. He knew the mind of the British sailor better than most and from him stemmed a whole series of ideas by which his officers and ship's company devised recreational activities and evolutions that passed the time and made it seem to hang less heavily than it would otherwise have done. In another context much of this activity would have seemed frivolous: childish even, but frivolity was exactly what was required and none saw that more clearly than John Gower. There were relay races round the ship in fancy dress, quizzes, darts tournaments and the inevitable 'uckers:' ludo to anyone else, but a good deal more complicated than the nursery variety.
Eventually the Mosaic II bomb, much larger than its predecessor, was detonated. Diana and her people, did what she had to do, and then it was over. There was nothing for which she needed to go back to Monte Bello. A little jaunt to Fremantle would have been regarded as a great treat but the ship and her people were decidedly unwelcome there and so she headed once more for the steaming lushness of Singapore. This was not her ultimate destination, of course. Though the Mediterranean had been put to the back of the collective mind, the Dianas were always aware that it was to Malta that they must eventually return.
After a little work in the dockyard at Singapore the ship headed up the coast for a few days in Penang and then across the Bay of Bengal to Madras, a teeming city where raw poverty so openly visible on the streets shocked many of Diana's young sailors. She then proceeded to Trincomalee in Ceylon, the great anchorage that had long been the Royal Navy's principal base in the Indian Ocean. After 'Trinco' Diana headed westward into the Arabian Sea and was some way from India, though a couple of days short of Aden, when news came through that was to shape the ship's activities and the men's lives over the next year in a way that Diana's sailors could not have anticipated.
It was revealed that the Egyptian president, Gamal Abdel Nasser, had nationalised the Suez Canal in the face of protests from the principal shareholders, Britain and France. These two major powers were clearly not going to accept such a situation, and warlike preparations began at once for possible action against Egypt. Diana did not return to the destroyer group in Malta but remained in Aden where she became part of a naval force hurriedly assembled there. Shortly after Diana's arrival the cruiser Kenya turned up, large and menacing with her three triple six inch turrets. Indeed, shortly afterwards there arrived from the Far East a sister ship, HMS Newfoundland, and the busy harbour of Aden was dominated for a time by these two Fiji Class cruisers. Kenya soon left for home but the presence of Newfoundland lent a constant air of reassurance. Other vessels arrived from the Far East, principally the Black Swan Class frigates, Crane and Modeste.
Eventually the situation in the Middle East flared up into a real, though brief, war and Diana was involved in action of a kind for which she was far better suited than that which had taken place at Monte Bello. Eventually, shortly before Christmas, she sailed from Aden for the last time. She could not, of course, make her way through the Suez Canal, as that had been blocked by the Egyptians, and instead she turned her bow to the south and headed for the Cape of Good Hope, eventually returning to Devonport in February. After refitting in the dockyard she joined the Home Fleet and ended her commission with a circumnavigation of the British Isles.
Diana paid off in August 1957. Her crew dispersed and, as so often happens in the Navy, many of the men were never to see each other again. However, a group of Dianas from Liverpool kept in touch over the years and in 1986, thirty years after joining the ship, they organised a reunion which was to become a happy and highly successful annual event. Prominent among those attending were Captain John Gower and his First Lieutenant, Commander Pat Ellison, men of presence and stature who remained greatly esteemed by the Dianas in their later years, just as they had been in the trials and dangers of youth."