Dominic Lawson: After turning Mugabe from friend to foe, we have been haunted by our colonial past

Robert Mugabe is a much–misunderstood man. I don't mean that he is the virtuous leader of his own imagination – nothing could be further from the truth; but he is equally far removed from the caricature African dictator who eats the testicles of his enemies for breakfast.

A friend who had known him for many years once described him to me as "urbane, witty, sophisticated, sensitive, thoughtful – and ruthless". These, presumably, were among the attributes which impressed the British when they got to know him during the Lancaster House negotiations of 1979 which paved the way for Mugabe's now 27-year-long rule in Zimbabwe.

The affection was mutual: the same friend told me that on the death of Sir Christopher Soames – the British Governor during the transitional period – Mugabe flew to Britain with a Union Jack which he tearfully laid on Soames's coffin. Despite the fact that he had suffered much under the Rhodesian regime – the then Prime Minister, Ian Smith, had refused to let Mugabe out of jail to attend the funeral of his four-year-old only son – Mugabe treated his old adversary with a certain courtesy. He preached the idea of reconciliation between whites and blacks some time before Nelson Mandela became celebrated for espousing the same admirable doctrine.

As if to demonstrate that, for at least the first 15 years of his rule, Mugabe did his best to protect the 5,000 white farmers who controlled 75 per cent of the country's farmland – despite the fact that most of them showed absolutely no inclination to train up their indigenous workforce.

By contrast, Mugabe's treatment of the minority black tribe, the Matabele, was savage.In 1984, Mugabe's Shona clansmen massacred an estimated 20,000 of their ancient tribal enemy – almost all of them civilians. The British reaction to this was interesting. It did not stop the Conservative Government from awarding Mugabe an honorary knighthood; while the British Left, in general, took the view that it would be a display of colonialist arrogance to seek to interfere.

This desperate concern not to appear "colonialist" has paralysed Britain's policies towards Zimbabwe ever since Labour came to power 10 years ago. This is in a way rather odd: such anxieties did not stop Tony Blair from committing British troops to the invasion of Iraq – a country which was invented by the civil servants of the British Empire – neither did it prevent Blair from sending in our armed forces to try to sort out Sierra Leone. Moreover, such oppression as Mugabe and his Zanu–PF band of brothers endured had not been at the hands of the British state but of a rebel regime which had declared Unilateral Independence from Britain and the Commonwealth.

It took a black public figure, John Sentamu, to say what no white politician has dared to utter. Last weekend the Ugandan-born Archbishop of York declared that "Britain needs to escape from its colonialist past when it comes to Zimbabwe. Mugabe is the worst sort of racist dictator. The time for African solutions alone is now over ... it is time for the sanctions and campaigns that brought an end to apartheid in South Africa to be applied to the Mugabe regime." Gordon Brown has risen to the challenge ... by refusing to attend the forthcoming EU-African Union summit in Lisbon unless Mugabe is disinvited.

Like most (if not all) sanctions, this has the effect of making us feel slightly more virtuous while doing nothing to end the oppression it is notionally designed to deter. I would imagine that Robert Mugabe would be delighted if his presence in Lisbon turns out to be the cause of Britain's absence from the table; and if Portugal should rescind its invitation, does anyone seriously imagine that this would do anything to put a single extra gram of maize into the mouths of Zimbabwe's children – or accelerate by one second the ending of Mugabe's rule?

The "time for sanctions", as John Sentamu puts it, is well and truly over – even supposing that there ever would have been a point. The view that it was sanctions that brought an end to white apartheid rule in South Africa is a common misconception. It was the end of the Cold War which finally isolated South Africa politically from the West: it was no longer seen as a bastion against communism in its own continent. The same historical watershed had a tremendous influence on Pretoria: it could no longer pretend to its own people – or to itself – that it was defending them against the local outreach group of the Soviet dictatorship.

Mugabe, too, disavowed his Marxism when the Soviet regime fell – although the corruption of his Zanu–PF cadres is as crude a demonstration of brute political power as any one-party state could devise. It was, in fact, the Blair government's concerns about the allocation of spoils to Mugabe's cronies which caused the transformation in Mugabe from faithful friend to bitter enemy.

Under the Lancaster House agreement with the government of Margaret Thatcher we had pledged to finance the compensation to white farmers as their farmland was gradually handed over to black Zimbabweans – who in practice were always going to be Mugabe's mates. On 5 November 1997, however, Claire Short, then the Secretary of State for International Development, wrote an astonishingly ill-judged letter to the Zimbabwean Minister of Agriculture and Land, Kumbirai Kangai.

It brusquely cast aside all previous undertakings: "We do not accept that Britain has a special responsibility to meet the costs of land purchase in Zimbabwe. We are a new Government from diverse backgrounds without links in former colonial interests. My own origins are Irish and as you know we were colonised not colonisers."

It would have been hard to construct a letter more skilfully designed to enrage Mugabe – or even a man with a much thicker skin than the Zimbabwean leader. Short's amazing assertion – that because her family was of Irish stock there was no need to honour a commitment to Zimbabwe entered into by a previous British government – was an inimitable mixture of shamelessness and sanctimony. That friend of mine who knows Mugabe says that Short's letter sent him into a rage against Britain which has scarcely abated for the succeeding decade.

Who knows, perhaps it was awareness of his own minister's responsibility for the quite unnecessary transformation of Mugabe from friend to foe which deterred Tony Blair from applying his doctrine of liberal imperialism to Zimbabwe. In any case, New Labour has learnt from its adventures in southern Iraq that it is relatively straightforward to kick the door in: it's quite another matter to clear up the mess afterwards.

Dire beyond belief as the plight of Zimbabwe is, the only people who should put an end to the tyranny of Robert Mugabe are his own – and they will.

d.lawson@independent.co.uk