Robin Harris: The war that made Thatcher and put iron back into Britain

All wars are in an obvious sense avoidable, and so was the war waged 25 years ago for the Falkland Islands. The Argentinian junta could have concentrated on overcoming internal problems, rather than manufacturing an external distraction from them. It chose not to do so. The Reagan administration could have signalled much earlier its opposition to such a mad venture. It preferred to equivocate, so as to retain the bibulous and unpredictable General Galtieri as an ally in its wars in Central America.

For its part, Britain could simply have accepted the invasion as a fait accompli, which the Ministry of Defence initially recommended. Nothing, after all, is a surer antidote to hostilities than immediate surrender. But, then and since, Baroness Thatcher's critics have suggested another option - namely that the Government could have avoided the war altogether by deterring it.

In this week's Spectator, for example, Simon Jenkins slams Lady Thatcher for "appeasing islander opinion" while "cutting defence spending" and "signalling that [the Government] had lost interest in its South Atlantic possessions".

It is an old tune that does not improve with the years. Six months after the victory, the Franks committee, whose membership included two senior Labour politicians, concluded: "We would not be justified in attaching any criticism or blame to the Government for the Argentine junta's decision to commit its act of unprovoked aggression." One could quarrel with the emphatic phrasing. Yet the judgements in the report - not all of which were so positive - have largely stood the test of time.

The recent official history of the campaign by Sir Lawrence Freedman comes to broadly similar conclusions. Freedman adds, though, two qualifications. He places the junta's decision to invade earlier than was thought, which other Argentinian sources also confirm; so there was at least a potential window within which deterrence might have worked. Second, he notes the failure (of successive British governments) to face up to the need to choose between a "Fortress Falklands" approach - requiring a whole-hearted and expensive military commitment - or a diplomatic approach - requiring, in the last resort, a willingness to over-ride the islanders' wishes and concede sovereignty to Argentina. But Franks was right, all the same.

The reason why can only be understood if one also grasps the distinction, dear to the former US defence secretary Donald Rumsfeld, between the "knowable" and the "known". The Thatcher government faced an inescapable dilemma that stemmed from lack of information. It had to explore whether the Falkland islanders were willing to accept a cession of British sovereignty to Argentina, with a period of continuing British administration under the so-called "lease-back" arrangements. When the islanders rejected that option, and when Parliament also made it clear that the Falklanders' wishes must not be over-ridden, a diplomatic outcome was rendered impossible.

Yet diplomacy had to continue, for the simple reason that it alone offered time for an alternative British strategy to be developed. To have embarked at this point on a military build-up - enlargement of the garrison, extension of the airport runway, the despatch of ships and submarines, cancellation of key aspects of the Defence Review - would have been very risky. If the Argentinians had not been planning an invasion, this might well have provoked it. If they were planning one - as we now think they were - it could have precipitated it.

The British, in fact, faced one of Rumsfeld's "unknowns". They did not know Argentinian thinking, and so did not successfully predict Argentina's decisions. There was no intelligence cover-up. There was merely a succession of minor intelligence cock ups - of the sort that frequently precede war, but do not cause it.

Whether or not the Falklands War was avoidable, it was, by contrast, always eminently losable. Lady Thatcher understood this when she sent the taskforce, and the appalling possibilities filled her waking, and not a few of her sleeping, moments for the next 11 weeks. But the risks were not fully grasped by the general public.

Nor were they understood by the MPs braying for ministerial blood during Saturday's noisy debate on the eve of the dispatch of the taskforce. Tony Blair has subsequently said that he would have sent the taskforce, which is probably true. But sending it was the easy part. Whether he, or any other modern prime minister for that matter, would have resisted the pressure to delay it and then confounded attempts to prevent its use is much more questionable.

The military threat posed by Argentina was much greater than a comparison between the two adversaries' forces might suggest, because of the multipliers provided by geography - distance from Britain, proximity to Argentina - and the weather - winter closing in from the end of May. On top of that, had the US not provided Sidewinders for British Harriers, had the Argentinians replenished their stocks of Exocets, or had the Argentine navy matched its pre-war belligerence with effective aggression, the outcome could have been altogether different. Above all, one disaster, such as the loss of the Canberra or the disabling of a carrier, could have seen the Cabinet's morale collapse in an instant.

Indeed, the most likely way in which the war would be lost was always through political confusion or weakness. To avoid that fate, Lady Thatcher had to show strengths as a war leader which no one could have expected of her. She had, on the one hand, to be prepared for tactical compromise, because otherwise Britain's diplomacy would have been frustrated and she risked losing the civil war being fought within the Reagan administration between Latinos and Anglophiles. But she had equally to avoid any diplomatic "solution" that ruled out a return to the status quo ante bellum, which would have effectively ceded the islands to Argentina.

Above all, it was necessary to coordinate the diplomatic and military initiatives in order to ensure that the former never put the latter at risk. This is what her Foreign Secretary, Francis Pym, seemed incapable of grasping. He bent so far to American demands that the troops aboard the taskforce could have been left wallowing in the storms of the South Atlantic until weather made the operation impossible. Lady Thatcher had planned to resign as Prime Minister if the terms with which he returned from Washington were accepted by her colleagues. But she won her argument, and so Britain was able to win back the Falklands.

Lady Thatcher's task as chairman of the War Cabinet was to put hard questions to the military - harder than Mr Blair seems ever to have done - while meeting their mounting demands for men and materiel. It was also to set the rules of engagement and to authorise any departures from them.

The most important decision of this sort was that to sink the Belgrano. (She would also have authorised an attack on the Argentine carrier 25 de Mayo, but it slipped the net.) Because the enemy navy henceforth remained in port, a successful amphibious landing could be conducted without air cover - a notoriously dangerous undertaking. The howls of outrage that greeted the sinking of the cruiser were thus drowned out by cheers when British forces landed at San Carlos.

Twenty-five years on, it is possible also to give a clearer answer to the question: was the Falklands War worth waging? Despite the loss of 253 British (and 649 Argentinian) lives, the answer is undoubtedly, "Yes". Not primarily because the Falklanders were able to determine their own way of life, important as that was. Nor because the natural resources involved have turned out to be far more valuable than anyone thought at the time, which they are. Rather, because to have yielded without a fight, or worse still to have been defeated, would have resulted in total national humiliation. In these circumstances Britain could not have remained a major power or an effective ally in the Cold War.

Of course, it would also have meant the fall of Lady Thatcher. Had she lost the Falklands, it is doubtful she would have wished to continue. Her departure would have halted and probably reversed the economic reforms responsible for Britain's subsequent economic revival.

But, above all, victory in the Falklands did something else: it contained within itself the unique balm to heal the scars left by Suez, a quarter century earlier. Not just the politicians but also officials and the military men were always conscious of that miserable precedent. The commanders and the civil servants half-expected to be let down again by the politicians. The politicians half-expected to be let down again by America. Neither eventuality occurred. But both were always possible.

Lady Thatcher was never temperamentally interested in reflecting on history. She preferred to make it. But she understood then, and she understands now, that the Falklands War was the most important episode of her premiership. Of course, at one level, Max Hastings, who similarly made his name in it, is right to call the Falklands a "damnably silly conflict". Britain was fighting a lonely struggle thousands of miles away from its shores for aims that made little or no sense to anyone else. But for that very reason it was of transforming intensity.

Unlike New Labour's wars, it was a national struggle for British honour and interests. This anniversary is a reminder that decisive leadership is always at some stage most likely to involve iron and blood.

Robin Harris was a member of Margaret Thatcher's Downing Street Policy Unit and is writing a biography of the former prime minister