It's been billed as the most important international summit in recent years, but what can the G8 really hope to achieve? Nick Morrison looks at the collision between expectation and reality

International summits are renowned for failing to meet even modest expectations. Several days of talks are invariably followed by a bland communiqu, often long on good intentions and promises to work together, and short on detail. And even these are often quickly forgotten.

But never has a summit been so loaded with hope as this week's gathering in Gleneagles. The millions of people who watched Saturday's Live8 concerts around the world have been led to believe that this is an historic opportunity, that the leaders of the G8 group of nations meeting over the next day-and-a-half could solve Africa's problems, if only they had the will. That they have the chance to Make Poverty History.

By hitching his wagon to Bob Geldof's band, Tony Blair is hoping to rebuild some of the trust he has lost at home, as well as cement his reputation as an international statesman. His public commitment to tackle global poverty appeals most to the very people who are least interested in politics, and least likely to vote, the under 30s.

But it is also a high-risk strategy. If there is no substantial progress and potential glory is snatched away, heightened expectations mean there is further to fall if the summit is branded a failure.

Some degree of success is already assured. A whistle-stop pre-summit tour of the G8 nations has helped broker deals on two of the main planks of the Prime Minister's African agenda, debt and aid (see Q&A). But there are major sticking points on the third part, trade, not to mention the fundamental differences over climate change which could provide the biggest disagreements of all.

And if anyone can spoil Mr Blair's party, it is expected to be French President Jacques Chirac. Relations between the two were brought to a new low in a row over the EU budget in Brussels last month, and descended into further acrimony with President Chirac insulting British cuisine over the weekend. Whether he will find the five star Gleneagles Hotel, where rooms start at £555 a night including dinner and a round of golf, to his liking, may shape the summit's prospects.

M Chirac will fly to tonight's opening dinner at Gleneagles from Singapore, where he has been pressing the case for Paris to host the 2012 Olympics. The result will be announced while he is in the air, and British officials are nervous that a London victory would be a humiliating blow which would infuriate him still further, and increase the chance of him wrecking the summit.

But if British food has given President Chirac indigestion, the invasion of Iraq has opened up wounds which are yet to heal. And, although the French are largely supportive of British initiatives on aid and debt, they are determined to maintain the Common Agricultural Policy (CAP), one of the major obstacles to creating a level playing field on international trade.

German Chancellor Gerhard Schroeder was also an outspoken opponent of the war in Iraq, and is said to be still angry with Mr Blair. The Germans, along with the Italians and Canadians, also resent what they see as being caught in the Blair-Geldof ambush and railroaded into signing up to give more aid to Africa.

If Mr Blair hoped his support for military action would earn him a quid pro quo from the US, he would have been disillusioned by President Bush's comments in an interview on ITV on Monday that he would not be doing his special friend any special favours.

The White House remains one of the chief barriers to a deal on trade. Although President Bush has indicated he could scrap subsidies to American farmers if the EU abolishes the CAP, he did this in the knowledge that it is a bluff that will never be called.

Just as damaging to the summit's chances of success is US intransigence over climate change. In this, President Bush finds himself in a minority of one among the G8 leaders, but as the overwhelmingly dominant member of the group, the threat of isolation is unlikely to deter him from blocking a deal over global warming.

For all the talk of gasping an historic nettle, self-interest may dictate that this is yet another summit where expectation far exceeds reality. That significant work has been done on debt and aid only underlines how far hopes have been raised. All eyes may be on Gleneagles, but no-one should hold their breath.