They then produced a series of intercepted signals and other intelligence which left little doubt that an invasion was planned for the morning of Friday 2 April. We knew four things: that an Argentine submarine had been deployed to the area around Port Stanley…That the Argentine fleet, which had been on exercises, had broken up into smaller units and seemed to be reassembling for an invasion, that an army commander had been embarked separately on a merchant ship and seemed likely to be the commander of an amphibious force; and finally that the fleet had been ordered to destroy all its documents.35
Sigint might not have given early warning of Argentinean intentions, but now the invasion was under way, it rendered everything horribly transparent. This triggered action. Nott asked to see the Prime Minister immediately in her room in the Commons. An informal meeting of Ministers and Permanent Under-Secretaries gathered to discuss initial reactions. Margaret Thatcher recalls that the sigint from GCHQ was extremely compelling, and there was ‘no ground to question the intelligence’.36 She sent Ronald Reagan a message, ‘asking whether he was aware of the Signals intelligence that we had just received’. David Omand, Nott’s private secretary, was sent to see if the material from GCHQ had yet been forwarded to NSA. ‘At this early stage it had not.’37
Just before the meeting broke up, Henry Leach, the First Sea Lord, arrived outside the Prime Minister’s room asking to see Nott. They invited him in to join the proceedings. He entered in full uniform, making an immediate impression on the Prime Minister, who recalls it as a moment of ‘comedy’ in an otherwise dark episode.38 Thatcher asked him for his views. With ‘supreme self-confidence and assertiveness’ he explained that much of the British fleet just happened to be exercising off Gibraltar. It would be possible to send a large task force within a week. He predicted that the Argentines would flee at the sight of the White Ensign. Could he have permission? Thatcher acceded immediately and with visible relief.39 She already knew that her government was in very serious trouble, and the showing of her Ministers in the ensuing emergency debates did nothing to dispel the general air of incompetence.40 John Major, a backbencher at the time, recalls that an angry House of Commons was close to ‘mob rule’ and was febrile with ‘rumours that the Foreign Office had received the plans of the invasion days earlier’.41 Many have concluded that if the risky decision to send the Task Force had not been taken, the Thatcher government would not have survived.42
On Thursday, 1 April, further sigint arrived from GCHQ. The Argentine forces had been ordered to rendezvous off the Falklands at 6 o’clock the next morning, confirming the invasion date of 2 April suggested in earlier intercepts.43 How was GCHQ reading the Argentinean communications with such ease? The answer was quite simple. Some of Argentina’s high-grade military and diplomatic communications systems made use of expensive but thoroughly compromised European cypher machines, while some Argentinean military field units employed American-manufactured systems which were also vulnerable; oddly, their medium-grade traffic sometimes took longer to break.44 NSA also had the capability to read Argentine traffic, but was not giving it any priority due to its focus on Russia and China. In late April, Admiral Bobby Ray Inman, who was just completing his tour as Deputy Director of the Central Intelligence Agency (and who had been Director of NSA under Carter), explained the situation. US technical intelligence in Germany was now so good that a Russian surprise attack there was all but impossible. But, Inman insisted, Washington did not have ‘foreknowledge of the Argentine government’s intention to invade the Falklands Islands’. It just did not have enough staff to follow global trends, so in remoter areas it often did ‘very poorly’.45 In Britain, a number of senior ex-Ministers, including Denis Healey, who had taken a close interest in intelligence over the years, suspected that the Americans had known about the Argentinean invasion in advance. Antony Duff, who had replaced Richard Brooks as the new Cabinet Office Intelligence Coordinator, was busy giving private assurances to these individuals that this was not the case.46
GCHQ was now expecting a sigint bonanza. With Argentinean military operations rolling along, Cheltenham hoped that their readable communications, together with avid collection by friends and allies, would render their opponent an open book. They had not reckoned on Ted Rowlands, Labour MP for Clwyd, who had led the embarrassing negotiation mission to Argentina in 1977 as junior Foreign Office Minister. During his period in office he had been privy to sigint decrypts of Argentinean traffic. The word ‘privy’ is used advisedly, since he was now a Privy Councillor, a role to which special discretion is attached. However, in the heat of the Falklands debate in April 1982, he chose to blurt out all he knew about sigint. Anxious to extract maximum political advantage, he insisted that the invasion could not have been a surprise. ‘I shall make disclosure,’ he said rather pompously. ‘As well as trying to read the mind of the enemy, we have been reading its telegrams for many years.’47
The gasps of horror in the House of Commons were audible. The groans of agony were even louder at Cheltenham. No Member of Parliament had committed such a public sigint gaffe since Stanley Baldwin had infamously baited the Russians by reading out their own cypher traffic in the House of Commons in 1927. Margaret Thatcher later said that the Rowlands blunder had been ‘totally and utterly devastating in the amount which it gave away to those against whom intelligence was directed’, adding, ‘The moment you say too much the sources dry up.’48 What was the cost of the Rowlands security gaffe? Some have argued that it was so great that some major reverses of the Falklands War, such as the attack on the Sir Galahad at Bluff Cove, might have been averted had Rowlands kept his mouth shut.49 The reality seems to be that while the Argentineans may have improved their cypher security, their material became harder to break, rather than unbreakable. They improved their procedures, changed their codes more frequently and in some cases double encyphered, but to little avail, since their actual machines were compromised. Commander Robert Denton Green, who was the Intelligence Officer at Fleet Headquarters in Northwood, offers the best assessment:
But amid all this difficulty, GCHQ managed to break the Argentine codes. They were not terribly sophisticated, but we got a lot of very high quality political and battle-planning intelligence. It took us between twelve and twenty-four hours to decipher and translate the messages, so we were always trying to extrapolate forward to see what they meant for us now.
Denton Green concludes that although the material was sometimes ambiguous, GCHQ intercepts gave it a reasonable picture of what was going on inside the minds of the main Argentine commanders. By contrast, the GCHQ material on the political side was ‘a little bit confusing’, but this reflected the genuine turbulence within the ruling circles in Buenos Aires at the time. Some of the delay was caused by the challenge of sifting through the vast volume of messages that were intercepted and deciding what was useful.50 The Argentinean Air Force’s traffic was the hardest to read, since it had recently invested in new encrypted communications made by a subsidiary of the British defence company Racal, based in South Africa.51 One of the most irritating aspects of the Rowlands affair for GCHQ was that other countries in the Southern Hemisphere took the hint and set about improving their own cypher facilities.52
As the Task Force headed south, intelligence activities by other interested parties presented awkward questions. What should be done about the ever-present Soviet spy trawlers, ‘bristling with radio antennae’, that followed the Task Force?53 Overhead, they were watched by vast Russian TU-20D ‘Bear’ elint reconnaissance aircraft, with a range of eleven thousand miles, while GCHQ soon reported that the Russians had launched extra satellites to watch the spectacle.54 Remarkably, throughout the conflict the Norwegian signals intelligence base located at Fauske in the far north regularly intercepted the Soviet satellite intelligence data. This was then sent direct to the British, who used it to find the Argentinean fleet. One British intelligence officer recalls: ‘When the war broke out, we ourselves almost didn’t have any intelligence informat
ion from this area. It was here we got help from the Norwegians, who gave us a stream of information about the Argentine warships’ positions. The information came to us all the time and straight to our war headquarters at Northwood. The information was continuously updated and told us exactly where the Argentine ships were.’ Meanwhile, the Soviets passed nothing on to Argentina.55
In early April, Britain’s intelligence analysts were playing catch-up. One of the areas in which sigint offers huge benefits is its ability to build up a picture of the enemy’s order of battle, including the size of each unit, its position and the extent to which it is mobile. Partly because of the difficulties with high-grade Russian sigint during the Cold War, GCHQ and the sigint elements of the three services had devoted vast effort to mapping every subsection of Warsaw Pact forces. However, this sort of activity is time-consuming and labour-intensive. Armies of listeners are required to shadow the real armies on the ground. No such effort had been devoted to the armed forces of Argentina, and their order of battle was a mystery. Thus, on 4 April 1982, when Major General Julian Thompson, the Royal Marines commander, looked to his Brigade Intelligence Officer, Vivian Rowe, for a briefing about the three thousand Argentine troops, the main source of intelligence was reference books in Plymouth Public Library.56 Things did not look much better in the Defence Intelligence Staff in London, which had little material on the Argentinean order of battle. Eventually it found a British naval officer who followed the Argentinean forces as a hobby.57 Later, the CIA and Chile handed over their own order of battle materials on Argentina, which were complete.58
Meanwhile, Cheltenham had set up an operations room, presided over by Rod Little of K Division, the section of GCHQ that specialised in non-Russian comint, in one of the unprepossessing single-storey spurs on the main site at Oakley. In a room nearby, elint was presided over by the head of J Division, Michael Herman, who had vast experience of airborne signals collection.59 One of the biggest problems was forward distribution of the product. At the Fleet Headquarters at Northwood, Commander Robert Denton Green had secure communications giving him an excellent feed of material from both GCHQ and NSA. However, the abiding Cold War mindset had resulted in little attention being given to the ability to push sigint forward to operational commanders, especially during expeditionary operations in far-flung locations. The main connection between GCHQ and Commander Sandy Woodward’s flagship in the South Atlantic, the aircraft carrier HMS Hermes, was a secure encrypted telephone link using Skynet, which allowed the operations room at Cheltenham to talk directly to the intelligence officers on the ship. However, distribution to lower levels was more difficult. As Denton Green observed, the Falklands War was ‘very strange’, and many arrangements had to be improvised.60
A set of bizarre circumstances soon made communications yet more difficult. In common with many British government agencies in the 1980s, GCHQ was now required to outsource its building maintenance rather than relying on a local workforce. Some weeks into the Falklands War, a gang of contractors appeared outside the Falklands operations room in Cheltenham and announced that they had come to resurface the roof. In times gone by they would have been sent away with a flea in their ear, but this would now involve hefty cancellation charges. So, with the nerve centre of sigint operations operating below, the labourers began work on the roof of the single-storey office building, ripping off the old felt, spreading fresh sealant and recovering. Vats of boiling tar surrounded the hapless sigint teams. As late spring turned to early summer the temperature rose, but the windows could not be opened. The tar men were not cleared for comint, or indeed any kind of ‘int’. For a week, conversations with HMS Hermes were hilarious. The intelligence officer on Woodward’s staff would say, ‘Hang on, I can’t hear you. Some Harriers are just taking off!’ Cheltenham would reply, ‘Well, we can’t hear you either, there’s too much banging on the roof!’61
During late April, even as the Task Force headed south, General Alexander Haig, Reagan’s Secretary of State, had been engaged in a slightly comic reprise of Kissinger’s famous 1970s ‘Shuttle Diplomacy’. Presenting himself to Margaret Thatcher as an honest broker, he had been subjected to a severe tongue-lashing by the Prime Minister, in which she made ready comparisons between the military dictators in Buenos Aires and Adolf Hitler. Despite her obvious vexations at American attempts to play the honest broker, Thatcher entered into the diplomatic exchanges in good faith. Rather to her relief, on 19 April the Argentinean government rejected Haig’s latest peace plan. Ronald Reagan now reluctantly terminated Haig’s mission, declaring American support for Britain. Britain announced a two-hundred-mile Exclusion Zone around the Falklands. On 1 May the RAF launched the first long-range Vulcan bomber raid on Stanley airport. On the same day, Sea Harriers attacked Goose Green and three Argentinean aircraft were brought down. The talking was over and the shooting war had begun.
On 2 May, the most controversial action of the war occurred when the Argentine cruiser General Belgrano was sunk by the British nuclear attack submarine HMS Conqueror. The Belgrano was a large cruiser accompanied by destroyers, and the British were anxious about losing track of her as she headed towards the Exclusion Zone. Her main threat was her powerful radar, which could detect the British fleet at long range, while the firepower actually lay with the Exocet-carrying destroyers that accompanied her. The Belgrano group constituted a serious danger to the Task Force, and was therefore being shadowed by the Conqueror under Commander Christopher Wreford-Brown, who had arrived on the submarine only a few weeks previously. The Admiralty requested a change to the rules of engagement to allow an attack on the cruiser while she was outside the Exclusion Zone, and the War Cabinet gave its approval at 10 o’clock in the morning. This had not been given lightly. Willie Whitelaw, the Deputy Prime Minister, asked what many regarded as the key question. If the Conqueror was asked merely to shadow the Belgrano group for the time being, could she be certain to maintain contact? The answer was an emphatic ‘no’. In fact, the Conqueror had previously been shadowing the Argentine aircraft carrier 25 Mayo, but had lost contact during bad weather.62
Even while this fraught discussion was going on, the Belgrano group changed course and, gently zig-zagging, began heading away from the Falklands. At 1.30 in the afternoon the Conqueror rose and accessed the satellite, which gave her the changed rules of engagement and permission to attack. Choosing old-fashioned Mark 8 torpedoes of a Second World War vintage,
Wreford-Brown had to manoeuvre to within less than two miles of the Belgrano. This took until 6.30 p.m. At the last moment he thought he had misjudged the approach. Peering through the periscope, he muttered, ‘Damn. Too close.’ But after a few seconds’ hesitation he fired three torpedoes. Less than a minute later, the first torpedo hit the Belgrano just ahead of the front gun turret. A massive flash lit up the sky, and the explosion nearly blew the entire bow of the ship off. The Belgrano was already doomed when the second torpedo slammed home. The third also found its mark, but failed to explode. The Belgrano was sunk thirty miles outside the Exclusion Zone, and 386 Argentine sailors perished. By the following day, all Argentinean naval vessels had been recalled to within a few miles of the coast.63
Sigint bears strongly on the Belgrano story. During the conflict, and for some years afterward, Margaret Thatcher was severely criticised for permitting the attack outside the Exclusion Zone. It now seems that the key signals intelligence concerning this controversial action reached British commanders and politicians in London after the fact. Events turned largely upon a sequence of Argentine Navy signals that were intercepted and read by GCHQ. On 1 May 1982 the Argentine Navy was told to locate the British Task Force around the Falklands and launch a ‘massive attack’ as soon as possible. The Belgrano was ordered south and into the Exclusion Zone. This alarming signal was intercepted by GCHQ, and strongly informed the government’s deliberations. Shortly afterwards, the War Cabinet met at the Prime Minister’s country residence, Chequers, and authorised an attack on the Belgrano.
Sigint showed that, although at this moment she still lay outside the Exclusion Zone, her orders were clear, and she constituted a serious threat. Later, further intercepted signals revealed that the Argentinean military chiefs had ordered the Belgrano to reverse course and resume her previous position, probably because she had been spotted by British aircraft. However, as we have seen, Argentinean traffic took some time to process, and the new intercepts were not distributed on the British side until the following day, and so had no impact on the day’s events.64 Accusations were later made that Thatcher pursued this action in order to ‘torpedo’ an American-backed Peruvian peace plan. It is now clear that the Belgrano was sunk for operational rather than political reasons.65
The Argentineans were not slow to respond. They deployed their French-built Super Etendard jets equipped with an air-launched version of the massive anti-ship missile, the Exocet. Almost everything that British intelligence thought it knew about Argentine use of this system was wrong. The naval operations staff in Whitehall had been assured that the Argentinean Exocets were not ready to be deployed.66 Although Britain knew the Argentines only had five missiles, they believed there was only one launch aircraft, when in fact there were five. The Task Force had been told the range of the aircraft was only 425 miles, but this did not take into account the possibility of mid-air refuelling. Thus, on 4 May, when the British detected an Argentine Neptune surveillance aircraft, they did not realise that it was helping to guide the attacking aircraft, and dismissed it as a search aircraft looking for survivors from the Belgrano. Only when two Etendards approached the Task Force, and rose slightly to acquire their targets with their radar, was the alert sounded. HMS Glasgow and HMS Coventry had mere seconds to respond, but escaped by firing large clouds of aluminium chaff, which deflected the missiles. However, twenty miles away, for reasons that are still obscure, HMS Sheffield had her radar turned off, and did not hear the warnings from her sister ships. Seconds later she was hit in the forward engine compartment by an Exocet.67 The missile failed to explode, but the ship was still destroyed by its force and its remaining propellant. Twenty members of the crew died. Everyone had known that the lack of air cover was the Achilles heel of the Task Force, and indeed, for this very reason some in the Cabinet had privately thought that its despatch was ‘ludicrous’.68
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