While I rejoice for him, I cannot forget that he is an ex-terrorist, though admittedly against a hateful, repressive regime. Many will excuse him on that account. I am certainly glad I was never called upon
to make such a severe moral choice.

But while he is receiving the plaudits, a certain savage non-event is taking place next door to his beloved South Africa on Friday – the day of a Hyde Park concert in his honour. Zimbabwe is holding a sham but blood-soaked run-off presidential election because it went wrong for Mugabe first time round.

There never was much point to it before Morgan Tsvangirai pulled out to save his supporters from a fate worse than death. That mad tyrant, Mugabe, claims only God can remove him from office.

While some of us wonder what stays God's hand, he has hamstrung the Opposition, his supporters have raped, burned, mutilated and killed opponents and ordinary hungry Zimbabweans have been made an offer they were not intended to refuse: vote Mugabe or (at best) stop a bullet.

Mugabe clearly thinks he is acting in the best interests of the black proletariat. He says he will not rest until every acre of land formerly in white hands is turned over to blacks – regardless, of course, of the resulting privation he never knows, unless the water supply in his presidential palace is no more reliable than it was when I visited Harare with Margaret Thatcher in the 1980s.

This obscene charade of an election has been conducted amid the smoke and stench of terror without a single word of condemnation from Mandela, the freedom fighter extraordinary. This is an astonishing failure by reputedly the most influential figure on the African continent.

What, I wonder, does Mugabe – and by extension any old black dictator in Africa – have to do to earn his moral condemnation?

For years, I have been asking the same question of the United Nations, the Commonwealth, the European Union and Britain, not to mention all those pious non-governmental organisations (NGOs) that seem to regard only whites as capable of racialism and oppression. No doubt some of them agree with Mugabe that Britain, not himself, is responsible
for the hell that Zimbabwe has become.

Of course, I ask the question not because I expect them to moderate the behaviour of despots but just to remind them of their responsibilities.

I would be naïve to suppose that they would do anything useful when not one of them represents the pure milk of democracy. In the Security Council China, for example, holds Tibet in subjection and Russia closes down newspapers that lampoon Putin.

The Commonwealth, over whom the Queen, God bless her, presides, is chock full of ill-chosen leaders whose main purpose in life at successive summits I attended was to lambast the UK over apartheid while holding out their hands for more filthy British lucre.

As for the EU, we know what reverence it has for democracy. Only the Irish have had the temerity to hold a referendum on the new EU constitutional treaty and have been called "bloody fools" by the French president for coming up with the wrong answer.

Britain is so addicted to democracy that our Prime Minister refuses a referendum on the EU treaty, even though his party specifically promised one at the last election.

Not that referenda have ever counted for much in Europe. If they go the wrong way, then – Irish please note – member-states can jolly well hold another until they get the "right" answer. If there is any difference in principle between the EU's approach to an election that produces an unacceptable result and Mugabe's, I am a Hottentot.

Meanwhile, the United States, the only – highly erratic – moral force of nature in the world, is preoccupied with fighting terrorism in Afghanistan and trying to democratise oil rich Iraq. Perhaps Mugabe survives – and his people die – because they have no oil.

Or perhaps not, if only Mandela could find it in himself to speak up. Even in his morally impaired state, Gordon Brown should at least shame him and the rest of the world into action by indicting Mugabe for crimes against humanity.