Forty years today on 2nd May 1982, during the Falklands conflict, the Royal navy submarine HMS Conqueror fired three Mk VIII torpedoes at the Argentine cruiser ARA General Belgrano. Two of them hit the cruiser which sank with the loss of over three hundred lives. (The official Argentine death toll is 323 though it was often alleged by people on both sides of the subsequent controversy that the Argentine authorities understated the casualty figures and that the real number of deaths was higher, with figures up to 368 being quoted.)
This action effectively took the Argentine navy, which up to that point had been a significant threat to the British task force, out of the war: Argentine surface and submarine naval forces retired to their territorial waters and made no further attempts to interfere in British operations to recover the Falkland Islands. This effectively doomed the Argentine garrison, though liberating the islands did not seem as easy or straightforward at the time as the scale of the British victory can make it appear in hindsight.
As Mrs Thatcher was subsequently to point out, only in Britain could a government face lasting criticism for an operation during a military conflict which removed a major enemy unit with no casualties on our own side and made it significantly easier to win that conflict.
Documents subsequently released demonstrate beyond reasonable doubt that subsequent allegations that the sinking was a war crime are without any valid basis in international law and are rooted in a misunderstanding of the facts.
In fact the only war crime in connection with the sinking was committed by the Argentine air force.
Much was made of the fact that the Belgrano was outside the "Total Exclusion Zone" at the time of the attack, but this zone was mainly a warning to neutral shipping. The British government had given clear warning on 23rd April 1982, more than a week before the attack on the Belgrano, that Argentine naval and air units operating in the vicinity of the Falklands Islands could and would be attacked if they were perceived as a threat to British forces, regardless of whether they were inside or outside the Zone or its predecessor.
Interviews with senior Argentine navel personnel published by Martin Middlebrook in his book "Argentine fight for the Falklands" make clear that they understood this. Rear Admiral Allara, commander of the Argentine naval task force of which Belgrano was part, said:
“After that message of 23 April, the entire South Atlantic was an operational theatre for both sides."
Of the allegations made in the years after the conflict by he so-called "peace movement" and by campaigners such as the late Tam Dalyell, they were correct on only one major point of contention, which was that the British government knew from intercepted signals exactly what orders had been given to the ARA General Belgrano and the rest of the Argentine Navy.
The British authorities did not want to confirm this for reasons which should be completely obvious to anyone with a higher IQ than a cabbage - the last thing you want your actual and potential enemies to know, if it is true, is that you have cracked their codes and intercepted their messages. But documents now released under the 30-year rule indicate that UK signals intelligence had done precisely that.
Unfortunately for anyone who wanted to prove Britain guilty of a war crime, far from having ordered the Belgrano to sail for home, the message which Britain had intercepted ordered the Belgrano to sail to a destination inside the "Total Exclusion Zone" and attack the British task force.
On the 1st of May 1982, Admiral Juan Lombardo had ordered the Belgrano and all Argentine naval units to seek out the British task force around the Falklands, and to launch a “massive attack” the following day. GCHQ intercepted and decoded that signal.
Regardless of the direction in which she happened to be steaming at the time of the attack, that cruiser was a threat to British lives and the people who ordered the attack on the Belgrano gave that order precisely because they had certain knowledge that she had been ordered to attack the task force and posed such a threat.
It is only fair to point out that even if the Dalyell and others had been right and the Argentine Junta really had ordered that Belgrano to return to base, and Britain had known this, the attack would still have been legal under international law and the UN charter. As an article in the New York International Law Review which came to that conclusion explained it,
"For the purpose of evaluating the legality of the Conqueror’s action, however, it is irrelevant. Even if the Belgrano flotilla had been ordered to withdraw, there is no suggestion that it had surrendered. Under international law, a military unit, even one that is retreating, is not entitled to safe conduct until it surrenders. It is the position of the U.S. government, for instance, that “the law of war permits the attack on enemy combatants and enemy equipment at any time, wherever located, whether advancing, retreating, or standing still.”"
The timing of events and the subsequent diplomatic positions of both governments involved does not support the suggestion that the attack was an attempt to derail the Belaunde peace plan, as Lawrence Freedman shows in the Official History of the Falklands Campaign which dismisses any such idea. Mrs Thatcher and the UK government did not see the plan until after the sinking of the Belgrano, but were subsequently supportive of it: it was the Argentine Junta which refused to consider it.
After the Belgrano went down the British government ordered HMS Conqueror not to attack any Argentine vessel which appeared to be searching for or picking up survivors - an instruction which was. of course, scrupulously obeyed - and permitted the Argentines to send aircraft to search for survivors.
This restraint was not rewarded: the one real war crime in connection with the Belgrano sinking is that Argentine Neptune aircraft engaged in the search for survivors also used their EW capabilities to search for the British task force and passed back intelligence about the location of Royal Navy vessels. This intelligence may well have contributed to the loss of HMS Sheffield two days after that of the the Belgrano. This was a breach by Argentina of the Geneva Convention, which forbids aircraft involved in rescue missions from also taking part in offensive operations.
Mrs Thatcher always said that when the facts about the decision to attack the Belgrano came out she would be vindicated. There will always be some die-hards among both Argentine nationalists and the British people whom no evidence could convince, but most people capable of taking anything remotely resembling an impartial view will come to the conclusion that the evidence does indeed vindicate her actions.