Leading article: Brown's opportunity to help Africa

This year's G8 summit, which kicks off today in Hokkaido with Gordon Brown in attendance, may be one of the last of its type, for a consensus has grown that a club uniting only the US, a clutch of European states and Russia can no longer claim the right or ability to steer the world economy. But if the need to expand the club to make it more effective is pressing, it is also no excuse for inaction this year.

The danger at all these international gatherings is that the agenda becomes long and loose, covering everything and nothing. This year, too, it is hard to see more than pious phrases emerging from a discussion on the environment. However panicked we are in the post-industrial West about global warming, the industrial ambitions of India, China and Brazil will not easily be thwarted. It is the same with fuel. Sky-rocketing oil prices are high on the agenda of almost all inhabitants of G8 countries. But with Russia the only major oil producer in the club, it is not easy to see what levers the summit can pull over petrol prices.

That leaves food shortages, or rather the growing shortage of affordable food, which threatens to wreak devastating consequences in parts of Asia and Africa. Here the G8 can make an appreciable, immediate difference.

Even in wealthy Britain, where food makes up a paltry nine per cent of average budgets, families are feeling the squeeze from rising food prices. In the developing world, where food can make up 80 per cent of budgets, the sudden jump in the cost of rice and maize threatens the wellbeing of huge populations.

The factors behind this range from population surges in the Third World to changes in land use in Western countries towards the production of biofuels. Those vast granaries, America and Canada, could do something here, measuring the benefits of growing biofuels against the effect of this trend on world food prices.

All G8 countries, meanwhile, could increase funding for agricultural projects in Africa at the same time as living up to their 2005 Gleneagles commitments to increase overall aid to Africa. If the results of this combination pushed up food production in Africa by even only a few percentage points, that would still help millions of people.

Some people may feel tempted to wash their hands of Africa, disgusted by events in Zimbabwe and the African Union's feeble response. This would be a mistake. Mass starvation in Africa will cost far more to address through food aid, delivered post facto, than pre-emptive action now through investment. Hokkaido could be Gordon Brown's moment. He knows more about Africa than his fellow delegates, and his commitment to the continent is well known. He must make his voice heard.