While US tries to inject purpose into meeting, Italy is lambasted for poor planning and reneging on overseas aid commitments

Preparations for Wednesday's G8 summit in the Italian mountain town of L'Aquila have been so chaotic there is growing pressure from other member states to have Italy expelled from the group, according to senior western officials.

In the last few weeks before the summit, and in the absence of any substantive initiatives on the agenda, the US has taken control. Washington has organised "sherpa calls" (conference calls among senior officials) in a last-ditch bid to inject purpose into the meeting.

"For another country to organise the sherpa calls is just unprecedented. It's a nuclear option," said one senior G8 member state official. "The Italians have been just awful. There have been no processes and no planning."

"The G8 is a club, and clubs have membership dues. Italy has not been paying them," said a European official involved in the summit preparations.

The behind-the-scenes grumbling has gone as far as suggestions that Italy could be pushed out of the G8 or any successor group. One possibility being floated in European capitals is that Spain, which has higher per capita national income and gives a greater percentage of GDP in aid, would take Italy's place.

The Italian foreign ministry did not reply yesterday to a request to comment on the criticisms.

"The Italian preparations for the summit have been chaotic from start to finish," said Richard Gowan, an analyst at the Centre for International Co-operation at New York University.

"The Italians were saying as long ago as January this year that they did not have a vision of the summit, and if the Obama administration had any ideas they would take instruction from the Americans."

The US-led talks led to agreement on a food security initiative a few days before the L'Aquila meeting, the overall size of which is still being negotiated. Gordon Brown has said Britain would contribute £1.1bn to the scheme, designed to support farmers in developing countries.

However, officials who have seen the rest of the draft joint statement say there is very little new in it. Critics say Italy's Berlusconi government has made up for the lack of substance by increasing the size of the guest list. Estimates of the numbers of heads of state coming to L'Aquila range from 39 to 44.

"This is a gigantic fudge," Gowan said. "The Italians have no ideas and have decided that best thing to do is to spread the agenda extremely thinly to obscure the fact that didn't really have an agenda."

Silvio Berlusconi has come in for harsh criticism for delivering only 3% of development aid promises made four years ago, and for planning cuts of more than 50% in Italy's overseas aid budget.

Meanwhile, media coverage in the run-up to the meeting has been dominated by Berlusconi's parties with young women, and then the wisdom of holding a summit in a region experiencing seismic aftershocks three months after a devastating earthquake as a gesture of solidarity with the local population.

The heavy criticism of Italy comes at a time when the future of the G8 as a forum for addressing the world's problems is very much in question. At the beginning of the year the G20 group, which included emerging economies, was seen as a possible replacement, but the G20 London summit in April convinced US officials it was too unwieldy a vehicle.

The most likely replacement for the G8 is likely to be between 13- and 16-strong, including rising powers such as China, India, Brazil, Mexico and South Africa, which currently attend meetings as the "outreach five" But any transition would be painful as countries jostle for a seat. Italy's removal is seen in a possibility but Spanish membership in its place is unlikely. The US and the emerging economies believe the existing group is too Euro-centric already, and would prefer consolidated EU representation. That is seen as unlikely. No European state wants to give up their place at the table.