Why give foreign aid at a time of austerity? According to a handful of Tory backbenchers and right-wing ideologues, it is all money wasted, squandered on bad projects and hijacked by corrupt politicians. But the Prime Minister went to New York yesterday to tell world leaders at the United Nations that they must keep their promises to increase spending on aid, as Britain has done. Quite right.
Last week, the latest figures showed that the number of children under the age of five who died from preventable causes in 2011 was 700,000 lower than the year before. That is the biggest annual fall in child mortality ever recorded. And it was not a blip. Some five million fewer children died last year than in 1990, with the fastest fall in numbers in Africa.
In no small measure, the improvements are down to the international community. Global aid has wiped out smallpox; it has controlled HIV and Aids in six million people; it has put 46 million more children into school in the past two decades; and it will vaccinate one child every two seconds for the next five years.
Critics can, of course, always find examples of aid programmes that fail. The National Audit Office recently found £48m spent on four poor-value projects. Yet the total aid budget is £8bn, and comprehensive studies show that most is far better spent today than even a decade ago.
That said, there is always room for improvement. That the newly installed International Development Secretary, Justine Greening, is scrutinising the £500m her department pays to consultants is, therefore, welcome. It is right, too, that aid to specific countries should be kept under review. India is now the world's 11th largest economy, with its own space programme no less. Development funding to the sub-continent must therefore taper off, though not so swiftly as to abandon the half a billion desperately poor people who live there.
New emphases are also needed. But there are no easy answers. A House of Commons select committee has said, for example, that the UK should use aid to help poor countries collect taxes from their citizens. But the process will be a slow one: even if India's middle classes were taxed 100 per cent of their income, dollar-a-day poverty there would fall by only 20 per cent.
Meanwhile, despite all this progress, 5,000 children die every day from preventable diseases. Modern medical technology means that if – as David Cameron demands – global promises on aid are kept, our generation could be the one that ensures no child dies of diarrhoea, pneumonia and even, perhaps, malaria.
There is an obvious moral imperative here. But we also act out of self-interest. A stable and growing world will provide a market of several hundred million people into which we can sell our goods and services. For every pound we invest in aid to Africa, we already gain almost two pounds back through trade. Aid reduces poverty and boosts private-sector growth. And kickstarting the economies of fragile states reduces the chance they will turn into breeding grounds for terrorism.
All of which costs less than a penny out of every pound of national income. Most people understand this. A 2010 poll found that 55 per cent of Britons think we should keep our promises to boost aid, with just 27 per cent saying we should cut it. We are voting with our wallets too; last year saw record contributions to charities like Save the Children and the highest-ever level of donations to Comic Relief.
Mr Cameron is right. Deficit or no deficit, Britain must not break its promise to the world's poorest.