Leading article: G8 must be judged by its delivery, not its rhetoric

Much of the credit for this can go to Bono, Bob Geldof and the Live8 concerts. But it is fair to say that Tony Blair and his Chancellor, Gordon Brown, have also done much to put this issue centre stage, along with global warming, by a persistent and sustained campaign over the past six months and more. Politics may have merged with celebrity in this case, but few could deny that it has been in a good cause.

The great question now, of course, is whether the agreements already made over debt cancellation and greater aid for Africa can be built on in the meeting itself, and whether the tide of public concern can be used to drive the process forward. It is a moot point. Mr Blair and Mr Brown have already achieved much on debt relief, they have managed to get the Europeans behind a substantial increase in aid and they have encouraged further assistance from a reluctant President Bush, but they are still far short of the kind of aid increases that the Commission for Africa was seeking as essential in its recent report or that the UN proposed in its millennium goals. As for trade reform, the issue which many feel is the most critical of all for the future of Africa, there seems to be little sign of agreement.

That matters because, in all the discussion about Africa's poverty and ill governance, one of the most encouraging signs has been the extent to which Africans themselves seem ready to grasp their own development future if the economic obstacles are removed. Trade is so much more important than aid; but it is also a far more difficult area for the industrialised nations of the G8 to make real concessions. Debt relief is a simple promise to make. But trade is complex because concessions will, inevitably, hit the West's producers and manufacturers. In the discussions over the next few days in Gleneagles, it is trade that will provide the real litmus test of the West's intentions.

In the same way, there need to be genuine targets set and genuine sacrifice on the part of the industrialised nations to make any sense of the G8's discussions on climate change. Better, says Mr Blair, to keep the US on board and the G8 unitedthan push for agreement to which the world's biggest economy and greatest polluter will never subscribe. That may be true in terms of getting a final communiqué in which the industrialised nations agree that climate change is for real and that something must be done. Even to get the US to sign up to that will mark some progress.

Given the scientific consensus that has now emerged and the clear signs of a warming already under way, however, it is just whistling in the wind. Add to that the more pressing economic concerns about rising oil prices, burgeoning trade deficits, Middle East peace and Afghan drugs that others want the industrialised nations to consider over the next few days, and you can sense how easy it will be to lose the key questions in a welter of well-intentioned promises amounting to very little.

Ultimately, it is the follow-up that will matter for this G8 meeting, as for its predecessors. The rhetorical part is largely achieved. It is the part that Mr Blair, as chairman, is particularly good at. But it is on the implementation - Blair's weakest suit - that the meeting will finally be judged, and with it Mr Blair's own desired place in history.