I have just watched tapes of Mr Dimbleby’s The New World War, the first part of which is to be broadcast on ITV late tomorrow night, Sunday. It is challenging stuff.

It is also strangely moving. Mr Dimbleby revisits two countries where he filmed early in his television career, and which draw him back. His professional reputation was at least partly based on a harrowing documentary he made about Ethiopia as a very young man; and he was in Beirut more than 20 years ago at the nadir of Lebanon’s fortunes; but, though the story he tells today is anguished, he shows a tenderness for these lovely and troubled places. In a media world where most of us flit from subject to subject wherever the news spotlight falls, Mr Dimbleby — older, greyer and sadder than the eager young chap with a 70s haircut of whom we see archive clips in Ethiopia — stays loyal to people, places and ideas, because he thinks they matter.

Though struck by the evidence he has gathered, I shall contest his central argument. So first I should say this: watch it if you can. The New World War is a thought-provoking piece of television reportage and commentary: honest, sharp, revealing, earnest, angry, personal and — praise be — never glib, the programme is a credit to an ITV which has found extended airtime for challenging public-interest television. They should do so more often and at a more civilised hour.

Dimbleby illustrates what he thinks connects George Bush and Osama bin Laden in a macabre waltz in which both men’s political survival depends upon their persuading their followers to see the world as being in a state of war. The US President’s Manichaean philosophy is well known: for him and for our own Prime Minister it really is as simple as good versus evil. “Either you are with us, or you are with the terrorists,” Mr Bush tells the camera. Bin Laden echoes this dualism precisely: the world, he says is divided “into two sides: the side of the believers and the side of infidels”. Mr Dimbleby invites us reject this simplistic way of seeing the world.

He then matches the dualism of bin Laden and Mr Bush with a dualism of his own. It is well put but not new: the familiar refrain of the British and European liberal Left and centre Left. This is that (just as Mr Bush or Bin Laden would say) modern international affairs are indeed characterised by the struggle of good and evil; and (just as Mr Bush or bin Laden would say) linkages and conspiracies can be found between apparently unrelated ills; and that (just as Mr Bush or bin Laden would say) good men must understand that their interests, however divergent they may seem, are bound together by a shared need to confound the conspiracy of evil.

It is just that liberals see a different evil: US interests, greedy and planet-wrecking consumerism, careless and callous globalisation. For them too (as for bin Laden and Mr Bush) beneath the surface of modern history — a surface on which problems bob around like so many free-floating corks — run invisible connecting strings. Understand these linkages (the argument runs) and we may learn how to secure the triumph of good over evil.

The New World War, thinks Mr Dimbleby, is a war against, yes, terrorism, but against poverty, injustice, disease, famine, pollution and drought too, because these evils feed the general evil — anger and despair — which drives men to extremist doctrines and desperate remedies.

He makes the case eloquently. His survey of opinion in Lebanon paints a stunning picture of total and intractable Arab fury with America, Britain and Israel. But his attempt to carry this thesis over the Red Sea to Ethiopia and (by implication) more widely in sub-Saharan Africa, is less convincing. No doubt hundreds of millions of Africans live in dire poverty, and al-Qaeda are organising where they can, to exploit despair. If Mr Dimbleby has discovered that they are meeting with some success in the Horn of Africa, then I take his documentary’s word for it. But it is not my hunch that Africa’s chaos and furies are weldable by fundamentalist Islam into a single and potent fury against the West. Mostly, Africans kill each other. Desperate poverty disables rather than enrages or empowers. Iraqis (when I went there this year) were not desperately poor.

Crudely oversimplified, Mr Dimbleby’s argument is that if we cannot find ways for Africa to feed and water its peoples, they will rise up and kill us. I reply that it is worse than that. They will not rise up and kill us. Had they that power we might take notice of their plight. Africa’s collective failure robs its peoples of the means to make any collective threat. They will carry on dying, and it won’t affect us much at all.

Africa is not Arabia. Global warming is not a threat to Western values. Disease plays into no politician’s hands. Starvation may lead to revolution in one country, subjection in another, and we should help the poor because we should help the poor. My Pakistani friends talk more of Kashmir than they do of Israel. American intervention may have been right in Afghanistan and wrong in Iraq. To see the world in patches, dappled with rights, wrongs and maybes quite unlinked by the forces of good or evil, may be a mark not of failed intelligence but of the courage to venture out from beneath the wings of grand explanations of the world, and face each problem as individual.

I say of the British anti-American Left, as I say of both Mr Bush and bin Laden, that they should beware of failing to see the trees for the wood.

The New World War, ITV1, Sunday, October 31, 11.10pm; and Monday, November 1, 11pm

Contribute to the debate at comment@thetimes.co.uk

Times Recommends

• There's no future for prophets of doom
• New Labour family seethes with hatred
• Shallow, fake... Palin's beyond parody