It's a strange thing to be asked by the Archbishop of Canterbury to write an article. Particularly strange for me, as I'm one of the few people who would have been confused by his original letter. It asked me to write something for the New Statesman and was signed simply "Rowan". I assumed that it was from my old friend Rowan Atkinson and, although slightly puzzled by his new, fancy headed notepaper, I ignored it, as you're allowed to do with old friends. My office then received a prompting call. I reread the letter and realised that it was from a real, clever clergyman, rather than some­one who has just acted as stupid clergymen throughout his career.

But what to write about? I've been fairly scared of archbishops, ever since my first encounter with one on a train when I was nine. He sat down opposite me - we were travelling from Ascot to London - and I looked at him a lot. When I was finally convinced that he was Michael Ramsey, the archbishop of Canterbury (the purple dress was something of a giveaway), I asked him a question about God. He couldn't have looked at me in a more bored manner. He said it was a "very interesting question", then went straight back to reading his book without giving me an answer. So I was nervous of trying to get in touch with Rowan Not Atkinson and asking him a question, in case I got a similar reply.

I hope it's OK if I just write very quickly about malaria. I know I've got quirks but, now that I'm 54, I guess I have to accept who I am. I'll never understand classical music. I'll never get a glimmer of emotion from any painting by Picasso. I'll never like fish in any kind of white sauce. And I'll never understand why malaria is still killing over three-quarters of a million people, most of them young, every year, in this modern world of ours.

My sense of confusion was brought into focus by the letter that our Prime Minister, David Cameron, President Nicolas Sarkozy of France and President Barack Obama of the US sent to the major newspapers of the world in April. It was about something very urgent: the situation in Libya. They had to get together urgently because of the gruesome and dangerous situation that had arisen there. They had to take urgent action and they did. Urgent and expensive action - billions of pounds' worth of action.

What I don't understand is this: why are the lives at risk in Libya more valuable than the lives we are losing to malaria? I don't know how many are at risk in Libya, but I doubt there are 800,000. The total population of Libya is only six and a half million - roughly the same as the number of people who die of malaria around the world every eight years. Of course, oil may have something to do with it, but all of the rhetoric has been about human suffering. So it continues to puzzle me why these three powerful and important men don't write a letter to those same papers and say, "There's this terrible situation that is killing nearly a million people a year - 600,000 innocent children; more than 2,000 people yesterday - even though we know how to prevent these deaths. We must do something about it urgently."

Opening the box

One thing is for sure: they could be much more confident of the outcome of their initiative. Winston Churchill once said that as soon as you open the box marked "War", you have no idea what will happen:

Never, never, never believe any war will be smooth and easy, or that anyone who embarks on the strange voyage can measure the tides and hurricanes he will encounter. The statesman who yields to war fever must realise that once the signal is given, he is no longer the master of policy but the slave of unforeseeable and uncontrollable events.

This seems true in Libya and the other Arab spring nations. As I write, it is a fluid and dangerous situation. And the history of western support for revolution is littered with strange and unpredictable outcomes - see Osama Bin Laden.

But open the box marked "Malaria" and you will find a complicated plan for its elimination that nobody opposes. There's a long document called the Global Malaria Action Plan, which is a pretty good blueprint for success. There are a lot of brilliant people working on it. There has been a 20 per cent decline in deaths from malaria since 2000. During that time, 11 African countries have cut their malaria deaths by 50 per cent. The world did, in fact, almost get rid of malaria in the 1960s, but a bit stayed in Africa and now it's killing all over again.

This time we could win the full victory. So why doesn't it happen? Why do politicians seem to find lives at risk because of politics so fascinating but bide their time when it comes to lives at risk because of health? One answer, I suspect, is that it seems somehow more horrific for a life to be taken by a ruthless tyrant than to be taken by a ruthless disease.

I would argue that it's not. Spend a day at a hospital in Mozambique, Uganda, Nigeria or Burundi, where malaria is bad, and there's enough panic and horror and violence against children there for anyone's taste. See the looks on the faces of the mums and dads as their children sweat, vomit and slip into comas - they are no less full of horror than if a tyrant's bullet had caused the damage.

Another reason why there is so little sense of urgency in the face of the spectacular number of deaths from disease is that politicians are very, very interested in politics. We'd have a different world if it were run by doctors. You notice it with newspapers and the media, too - newspapers and the media love stories about the media and newspapers. There is no way that the public is as interested in the phone-hacking issue and the superinjunction furore as the newspaper column inches they've been given would imply. Editors love these stories because they're about their job. It is for the same reason that most politicians are interested in politics. They're obsessed by the Middle East - the ultimate political mystery - but they're not viscerally interested in medical questions. And they are not lobbied on medical questions with such vigour. In a world run by doctors, malaria would have been wiped out years ago.

Yet the truth is, if you want huge wins with predictable outcomes, they lie in the area not of politics, but health. And perhaps universal education (see Gordon Brown, overleaf). I would plead with David Cameron to think about making one of these issues his great foreign-policy cause. I'm particularly passionate about malaria but universal vaccination would also save millions of lives - rotavirus, which kills 500,000 children a year, could be wiped out. And universal education would transform the lives of 70 million working children. In a world run by teachers, every child would go to school.

Optimist that I am, I think perhaps things are indeed changing. I strongly applaud the Tories for recommitting to the last government's impressive promise that international aid should account for 0.7 per cent of gross national income by 2013. I've heard George Osborne talk passionately about the fight against malaria and I was thrilled. And the UK is co-hosting the crucial Gavi forum this month to find extra money for immunisation.

But I strongly encourage them to go a step further, to ask: "How can British leadership leave a mighty legacy in the world, change things permanently, quickly?" And then I think Cameron should ring up Nicolas and Barack in the middle of the night and say, "Let's write a letter to the papers again. I think we can do this. By the time we're out of power, we could save a million - no, if we really focus on it, five million lives a year, for ever."

Writing on the wall

I know I've got a simple view on it. I know I'm still just the boy in shorts asking the archbishop an obvious question. Nonetheless, I'm interested to know why this is such a foolish notion. Particularly if we have a dominant Obama winning a second term and doing some­thing serious about Africa while in power, unlike some Democrats before him.

One final statistic. At a rough count, the total number of lives - such precious lives - lost in the Middle East conflict since the Six Day War in 1967, added to the number of lives lost in the Troubles in Northern Ireland since 1969, added to the number of US soldiers lost in the Korean and Vietnam wars, added to the number of civilian and military casualties in our recent engagements in Afghanistan and Iraq, still has to be multiplied by two to get the number of lives that will be lost to malaria in the next 12 months. Precious lives, also. The combined cost of those wars is almostincalculable. But recent calculations say it would cost $6bn a year to get rid of malaria once and for all. That's 12 countries putting aside just half a billion each. But someone's got to lead it. Could it be our lot?

One final quotation. I went to a Roger Waters concert performance of The Wall the other day and up on the wall at one point came a quote I assumed was from the mouth of some noisy, bearded radical. It read: "Every gun that is made, every warship launched, every rocket fired signifies, in the final sense, a theft from those who hunger and are not fed, those who are cold and are not clothed." I was surprised when its attribution came up: Dwight D Eisenhower, supreme commander of Allied forces in Europe during the Second World War and Republican president of the United States. So, maybe it's me and Ike now asking the new generation of politicians: is there another way?

Richard Curtis is the writer of "Blackadder", "Four Weddings and a Funeral" and, most recently, "The Boat That Rocked"