SIGINT intelligence in the Falklands War

GCHQ is now well-known as being Britain’s most secret SIGINT intelligence agency. From its conception until now, it has been listening in to Britain’s enemies’ communications and helping shape British foreign policy since 1919. During the Falklands war, this was also true. Although there were some failings, SIGINT helped Britain win the Falklands war and helped to teach some important lessons for future engagements. 

1. SIGINT Failure in Early Warning

Many feel that GCHQ should have warned the government sooner of the imminent invasion of the Falklands. With hindsight maybe so. However, there are various factors that led to failures in detecting the coming invasion. Firstly, Argentina and South America were a low priority given the huge threat posed by the nuclear-enabled Warsaw Pact. So, although SIGINT traffic was being collected and disseminated, it was being done with fewer resources. 

Secondly, the preparations for the invasion were cut short. Argentina’s junta brought the attack forward, giving commanders just six days instead of six months to ready their troops. Without visible evidence of an invasion being prepared, usually over the course of months, very few people thought it a realistic possibility that Argentina would invade the Falklands. 

Thirdly, senior intelligence officers had seemed disinclined to change their stance on the possible invasion. The question had remained the same, ‘Will Argentina invade the Falklands?’, every time the answer was unlikely. Yet, as things progressed, the question remained the same. However, the answer remained the same. That was until Argentina invaded the island of South Thule, leading the Joint Intelligence Committee to conclude that the Argentine junta would use the Falklands as a cause celebre to generate popularity.

2. Britain’s SIGINT Capabilities

HMS Endurance was a Royal Navy ice patrol vessel that was used to ferry royal marines between South Georgia and the Falklands. Her bright red hull gave her the nickname ‘Red Plum’, but the friendly name masked her true capabilities. She was fitted with a listening suite that could pick up frequency bands at sea or on station.

 Along with her crew of sailors were two intelligence officers, nicknamed ‘the spies’, who were fluent Spanish linguists. Much of GCHQ’s best material on Argentina came from HMS Endurance. But in 1981, defence cuts were set to see her decommissioned. It was because of this that many in Whitehall believed her intelligence on Argentine SIGINT to be made up. It was deemed an attempt to extend the life of the ship and continue the roles of her crew. 

The invasion of South Thule had prompted Britain to revive its listening post on Ascension Island only a year after it had closed. This post would provide a position from which Britain could collect Argentine communications.

3. Britain’s Political Blunder

One of the most acute failures to British intelligence was the tragic show of Labour MP Ted Rowlands. After the invasion, GCHQ had expected a large amount of SIGINT from Argentina, however, it soon dried up. Ted Rowlands revealed to parliament that Britain’s SIGINT agency was listening to Argentina’s communications. This led to Argentina rethinking their cypher security, changing their cyphers more regularly, and sometimes double enciphering. This made their communications harder to read but did not make it impossible. It put deciphering time at GCHQ from 12 to 24 hours. 

Another blunder to the British system was that much of the intelligence was lost in parliamentary bureaucracy. Much of what was handed to policymakers was not properly heeded. However, Margret Thatcher was well-known for her avid interest in intelligence. The snippets of intelligence given to her in ‘the blue book’ would give her adequate information for moving forward. 

4. Britain Ruined Argentine Preparations

Ironically, it was Britain that spurred on the snap invasion of the Falklands. In March 1982, a group of Argentine metalworkers were contracted to remove old machinery from an abandoned whaling station in South Georgia. When they arrived, they hoisted an Argentine flag and refused to seek a landing permit, leading British Foreign Secretary Lord Carrington to order their removal. HMS Endurance was sent with a crew of 20 Royal Marines from the Falklands. In response, Argentina sent a similar-sized ship and landing force to counter the British. By the end of March, both countries had a force just 20 miles apart on the tiny island. 

This minor confrontation accelerated the junta’s plans to invade the Falklands. Argentine military officers had no time to prepare, and British intelligence officers had no time to see what was about to happen. The junta saw this opportunity, using the crisis in South Georgia as a pretext for the invasion of the Falklands. This extreme short notice helped the Argentines defeat SIGINT’s warning capabilities. 

5. Signals Started to Skyrocket

Around the 27th and 28th of March, GCHQ picked up communications from Argentina to her diplomats across the globe to cancel any leave and return to station. An ominous sign for intelligence officers in Britain. However, the JIC still believed in the gradual model of escalating tensions and did not think Argentina would order a snap invasion. 

HMS Endurance reported that Argentina’s rhetoric was increasingly bellicose and that Britain should prepare. This was seen as an attempt to prolong the life of the boat and was ignored. 

GCHQ started to pick up huge amounts of low-grade Argentine naval traffic. So much was collected that it became confusing and thus was given low priority. British intelligence had assumed that the invasion would be led by the Argentine Army, most of which was on the border with Chile. All of Argentina’s elite units were on the border too. 

However, the invasion was given to the Argentine Navy which had close connections with the junta. So increased signal traffic was actually preparation for war. 

6. SIGINT Gets a Hint

Finally, on 31st March, SIGINT picked up unmistakable signs of the Falklands invasion, with just two days’ notice. GCHQ picked up communications from the Argentine sub, Santa Fey, that they were landing a special forces recon unit onto the beach of Mullet Creek. 

During that morning, there had been a sudden increase in signals traffic leading intelligence analysts to the only possible explanation. The invasion of the Falklands was imminent. However, by 18:00 that evening, Secretary of Defence John Nott, still had no idea that a major crisis was about to unfold. He had been tied up in parliament all day and had not received the SIGINT intelligence. 

However, after sifting through the SIGINT he knew four things to be true. Firstly, he knew the Argentine Navy had a submarine sitting off the coast of Port Stanley. He knew the Argentine fleet, which had been on exercises and was split up into small groups, was now meeting back up into a large fleet. The SIGINT revealed that an army officer had embarked on a separate merchant ship who was likely the commander of the amphibious landings. And finally, and possibly most notable, was that the fleet had been ordered to destroy all its documents. There was only one conclusion: War. 

7. The Intelligence Battle for the Falklands

Although SIGINT had failed in its warning phase, it had rendered everything extremely transparent after the invasion was underway. On 1st April 1982, GCHQ had captured SIGINT confirming that the Argentine fleet was ordered to convene off the coast of the Falklands with the invasion to initiate the next morning.

Due to Rowlands’ blunder, GCHQ’s SIGINT intelligence was slower than before, and other countries in the southern hemisphere had also taken the step to change their SIGINT security. This made it harder for GCHQ to provide timely SIGINT intelligence to the British task force on its way to reoccupy the Falklands. 

However, Britain had other ways to gather intelligence. The British task force was followed by Soviet spy trawlers who were trying to listen in to British communications, overhead the Soviets flew TU20D bear ELINT reconnaissance aircraft. Ironically, the best source of intelligence for the British came from the Soviets. During the task force’s trip to the Falklands, the Soviet Union launched more satellites to cover the conflict.

The intelligence from these satellites was regularly intercepted by Norwegian SIGINT which was then provided to the British. The British used this intelligence to locate the Argentine fleet. The Soviets didn’t provide any intelligence to the Argentinians. 

8. General Belgrano

Possibly the most controversial encounter of the conflict was the sinking of General Belgrano. On the 2ndof May, a British attack submarine HMS Conqueror, launched three torpedoes at General Belgrano destroying it. Although quite antiquated at this stage, the British were anxious not to lose track of the Belgrano because of her powerful radar capabilities. Accompanied by two Exocet-laden destroyers, the ships were a dangerous group. 

The British Admiralty asked the war cabinet for a change to the rules of engagement so that the Conqueror could attack the Belgrano outside the 200-mile exclusion zone. This was accepted and the Belgrano was destroyed. However, the Belgrano was gently zigzagging away from the islands and further from the exclusion zone. 

SIGINT was crucial to this engagement; however, it has been revealed that the relevant intelligence reached the war cabinet after the fact. GCHQ had intercepted Argentine communications telling the fleet to locate and destroy the British task force as soon as possible. The Belgrano was ordered to sail south of the islands and into the exclusion zone, making it a direct threat to the task force. 

However, later SIGINT intercepts reveal that she had been ordered away from the islands, hence she was moving away from the exclusion zone. This could have been because the Belgrano had been spotted by British aircraft. 

9. Britain’s Communication Flaws

After British troops had landed on the Falklands, there were major communication issues between SIGINT analysts and ground troops. SIGINT continued to be fed to Admiral Woodward on HMS Hermes but a lot of this intelligence was deemed too high security to be communicated to Brigadier Julian Thomson’s intelligence staff. So the people who needed the intelligence the most were left in the cold. 

Information about Argentine unit sizes, equipment and locations was also hard to come by. So, the ground forces developed their own SIGINT collection. His staff picked up a local radio link that transmitted messages from Argentine troops on the Falklands to their families in Argentina. Not only were the messages not coded, they also used names, rank, unit, and location of the sender. 

It seems that defence intelligence knew about the numbers of Argentine forces at Goose Green, but this was not communicated to Colonel H. Jones, the commander of the 450 paratroopers who fought an Argentine force of four times their number. 

10. The Intelligence Gap

The intelligence gap between national institutions, the Army and the Navy, was filled by the soldiers of Y troop who developed their own SIGINT but also from local civilians who set it upon themselves to help British Forces. 

One such example was Charlie McKenzie. He was ordered to hand his radio to the Argentine forces. Instead, he gave them his backup radio so that he could listen to their communications. Argentina thought they were impregnable, due to being low power and short range. The most valuable intelligence he gave the British was that there were no islanders on the Stanley Airport Peninsula giving British artillery and air elements free reign to bombard the airport. 

11. Conclusion

On 15th April 1982 British forces captured Port Stanley and the Argentine forces surrendered. In the campaign SIGINT had provided 90% of intelligence. The biggest lesson was that most army units found themselves collecting highly strategic SIGINT that related to policy. Whereas SIGINT collectors using national resources found they were often collecting tactical intelligence relating to the troops on the ground. With SIGINT’s turnover time being too long to affect tactical decision-making, it became redundant as the battle changed hour by hour. The. System was not designed effectively enough to provide the correct intelligence to the correct actor. 

However, this does not diminish the important role played by SIGINT in retaking the Falklands. SIGINT was crucial. The lack of other intelligence sources such as imagery intelligence, due to cloud cover and lack of IMINT aircraft. The biggest problem to Britain’s highly effective SIGINT work was difficulties in communications leading to vulnerability to Argentine SIGINT. Therefore, the army needed to develop improved communications for the future. 

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