Two things strike me immediately about Britain on returning from a long spell in Africa. The first is its affluence: the fourth-richest country in the world, and it shows, despite all the inequalities. The second is the poverty of its ambitions: the inability to utilise this wealth to achieve any sort of meaningful change in the world, whether at home or abroad.

It doesn't do to become nostalgic about a time before you were born, particularly when it was a period that was dominated by the bloodiest conflict in human history. But a smidgeon of research I've been doing on the contrast between those two giants of post-war Labour politics, Nye Bevan and Ernest Bevin, makes it difficult not to despair at our lost sense of the possible in both domestic and international politics.

There, at the end of the second world war, was a battered, bloodied and impoverished Britain. But it was a country that never doubted that it could "afford" a National Health Service. And it was a country that, in spite of all the hardships at home, was prepared to introduce bread rationing in 1947 (after enduring the entire war without it) in order to send grain to Germany, which was on the verge of starvation.

That single act brings into sharp focus the practical, good-sense internationalism of a generation of political activists who had seen little of the world beyond their own borders, except in war. Without access to cheap air travel or the communications revolution of the modern mass media, they had more of a sense of being part of an interdependent world community than any number of the globalised jet-setters who were to follow. Whatever their flaws, the leaders of post-war Britain - and, more importantly, America - knew that there was more to winning a war than success on the battlefield. For all of its Bevanite past, what Tribune reader would not swap the Bevinite transatlantic alliance created in the 1940s for the version that exists today?

It's worth casting a comparative eye back to the 1940s, not least because the Prime Minister is doing likewise in his rhetorical war on terrorism. Tony Blair's speech to Labour's spring conference, hastily re-cast in response to the Madrid bombings, was generally described as "Churchillian", evoking the "spirit of the second world war". While the previous generation faced war with the Nazis, he told us, we face "a war of a different nature to anything before . . . terrorism waged without limits".

If Tony Blair spent more time studying history, rather than pondering his own place in it, he might have more of a sense of proper perspective. Al Qaeda and its allies have the ability to inflict awful pain, as they have shown in one atrocity after another, most recently in Madrid. But terrible as these may be, they do not bear comparison with the terror wrought by the Nazis; nor indeed with the routine toll of deprivation, starvation and disease that kills thousands daily worldwide.

Al Qaeda's are episodic, ugly paroxysms, not a sustained and serious threat to western democracy and freedoms. Some of the technology available to the Islamist-nihilists facilitates actions of a "different nature to anything before", and a globalised world makes possible a globalised terror network.

But unless you count only acts carried out in the last 60 years against countries of the first world, or you believe that terrorism is the sole prerogative of non-national, non-state groups, any half-serious historian would have to say that the world has seen terror "waged without limits" far more often, far more extensively and far more indiscriminately than the very worst that Al Qaeda is capable of attempting. Al Qaeda may have the capacity to hurt, terribly; but, unlike the Nazis, there is not a Christian in Mecca's chance that it can win.

How long it goes on hurting depends on how well we learn our history lessons. It goes without saying that we have to defeat - or, more realistically, contain - the terror networks of Al Qaeda and its ilk; and that there will be a price to be paid in doing so. Much more importantly, though, we must also be prepared to pay the price of the modern-day equivalent of exporting grain to post-war Germany.

Three weeks after the September 11 attacks on New York and Washington, Tony Blair delivered what was widely regarded as an inspirational speech to the Labour conference. He declared that, "The world community must show as much its capacity for compassion as for force." He said that, "The Palestinians must have justice, the chance to prosper and in their own land, as equal partners with Israel." And he described the state of Africa as "a scar on the conscience of the world". "If the world as a community focused on it, we could heal it," he argued. "And if we don't, it will become deeper and angrier."

In the weeks that followed there was much talk of a new "Marshall Plan for Africa", in reference to the economic aid programme for the rebuilding of Europe after the second world war. One month to the day after September 11th, the European Union launched its "New Africa Initiative". The following year, the G8 countries formally endorsed the "New Partnership for Africa's Development", or NEPAD.

"Fine words butter no parsnips," one of my African hosts told me (quoting Lenin, although he didn't realise it at the time) after one of the most recent NEPAD pronouncements. Buttered parsnips won't beat Al Qaeda on their own, but anyone with an understanding of history can tell you that they won't be beaten without them.