“We are far from pleased,” he said. “I find it singularly strange that Labour MPs can be welcomed on the floor of Congress but not at the Republican convention.”

In contrast to the previous occasion, he said, “they refused to budge”.

“They said they didn’t want any politician who wasn’t a conservative on the floor of the convention centre.”

A Republican party spokesman said no slight had been intended, and that the issue had merely revolved around the need to keep numbers on the floor of the conference down.

Mr Bush has given the British prime minster huge personal praise for his role in the Iraq war, calling Mr Blair a “stand up guy”.

But the mutual personal admiration between Mr Bush and Mr Blair does not readily extend to the political parties they lead.

Some Labour MPs are annoyed that the Liberal Democrats are making more of a showing at the Democratic convention in Boston than Labour.

A senior Labour strategist and minister, Douglas Alexander, is there, but no cabinet minister is attending.

The leader of the Commons, Peter Hain, will visit the Kerry campaign headquarters soon, but this is apparently in a private capacity, and he is not eager to discuss his visit.

However, they insisted that Bush had moved and, if he stuck to his promises, would provide 20 percent of the world’s aid going to sub-Sahara Africa by 2010, as well as 60 percent of the food aid.

Blair was informed of the Bush move Thursday morning, and his aides said the announcement, in conjunction with the previously announced debt relief package, “creates real momentum for a successful outcome.”

Hilary Benn, the international development secretary, said: “It looks as if we are almost there. It looks now as if we will reach the additional $25 billion in development aid for Africa by 2010 that the Commission for Africa said was needed in its report in the spring.”

The aid package came as the Paris Club of creditors unveiled a plan for the biggest debt relief package in African history, announcing it would open talks with Nigeria to eradicate $31 billion of debts within six months.

Nigeria, seen as the potential motor of the African economy, has been battling to fight corruption, and the announcement represents a triumph for the lobbying efforts of the Nigerian finance minister, Ngozi Okonjo-Iweala.

The new Bush package contained four elements:

– An extra $1.2 billion over five years aimed at halving the mortality rate from malaria in 15 African countries through new drugs and insecticide-treated nets. The program would start in Tanzania, Uganda and Angola next year, followed by a further four countries in 2007 and a further five in 2008. The mosquito-borne disease infects as many as 400 million people worldwide, killing 1 million a year.

– An extra $400 million over four years for America’s African education initiative, designed to train teachers and provide scholarships for 300,000 girls. Only half of African children complete primary education.

– An extra $55 million over four years to help with legal rights for women in four countries.

– Training of 40,000 African peacekeepers over the next five years as part of a wider G8 initiative.

The bulk of the proposed doubling in U.S. aid to Africa will come from already planned increases in aid to Africa set aside in the Millennium Challenge Account and anti-AIDS programs.

A Brookings Institution study released this week said that in 2000, the last year of the Clinton administration, total spending on African aid was $2.3 billion. The total for 2004, the last completed year of the Bush administration, was $3.4 billion, or just over a 50 percent increase. Much of the increase was in emergency food aid.

A study by the UNDP — timed to put pressure on G8 leaders ahead of their summit at Gleneagles, Scotland, next month — showed that based on current trends, the global community will miss by a wide margin the targets it set for poverty, infant mortality and education in the millennium development goals agreed to by the U.N. in 2000.

“These numbers should serve as a wake-up call for G8 leaders,” said Kevin Watkins, the director of the U.N.’s Human Development Report office. “Africa cannot afford to see the world’s richest countries sleepwalk their way to a heavily signposted — and easily avoidable — human development disaster.”

In 2000 the U.N. announced that by 2015 the global community would cut infant mortality by two-thirds, halve the number of people living on less than a dollar a day and put every child in school.

On the basis of current UNDP projections, there will be 5 million under-5 deaths in Africa, compared with 2 million if the goals were achieved; 115 million children deprived of an education; and 219 million extra people living below the poverty line.

The outline of a wide deal between George. W. Bush and Tony Blair on debt and aid for Africa took shape Tuesday night after lengthy talks between the leaders in Washington, which were seen as a test of Blair’s true influence over his coalition partner in Iraq. Blair wants to secure a landmark deal for Africa at the summit of G8 leaders in July but is battling against a U.S. administration under little domestic pressure to lift its aid budget.

Blair described talks on a debt relief package for Africa as “close to a deal. We are a significant way to a deal, and that would be very important if we could do that,” he said. “I am increasingly hopeful we can get a good deal on that.”

He conceded that “there are still issues that we need to resolve,” and that British hopes of being able to spell out the details of the package had been dashed, leaving further issues to be resolved at a meeting of G7 finance ministers chaired by Gordon Brown in London this weekend.

Blair acknowledged the details were intricate and that the U.S. was reluctant to fund interest payments to the World Bank in the event of total debt cancellation. A total cancellation of multilateral debt for the poorest African countries would be worth as much as $15 billion.

The prime minister also acknowledged that the Americans seem willing to boost their aid budget further, but only for specific programs covering issues such as water and vaccination. He also said that the U.S. would not fund an aid increase through the British Treasury’s chosen method of an international finance facility, a means of borrowing the money through the bond market.

Many aid agencies reacted angrily to the initial smoke signals emerging from the Washington talks. They feared a Bush offer to provide $674 million for famine relief in Africa represented the limit of American generosity.

Oxfam warned: “To drop the bar now and lower the ambition at this critical juncture would be seen by many as a betrayal.” It added: “Saving Africa has to be more important than saving Blair’s face.”

Blair also seemed to acknowledge that he faced an uphill battle in persuading President Bush to back mandatory limits on greenhouse gas emissions or to accept that the science on global warming shows the urgency for action. “It is important we recognize the need to take clear and immediate action, whether it is taken from the perspective of climate change or energy security and supply,” he said.

The science academies of the G8 states Tuesday issued a joint demand for action on climate change, saying it was “vital that all nations identify cost-effective steps that they can take now, to contribute to substantial and long-term reduction in net global greenhouse gas emissions.”

One source close to the negotiating process over the document, published by the U.K.’s Royal Society after months of discussions, called the support of the U.S. National Academy of Sciences for the document “unprecedented.” In 2001 the U.S. academy declined to sign a similar joint statement.

Blair, who will not attend the Live 8 concert in London even though he is delighted at the apparent success of the project, was lobbying Christian right and Republican senators Tuesday in to help create a political backdrop in the United States before which Bush would be willing to act. But with only weeks to the G8 summit and further shuttle diplomacy ahead in Germany, Russia and France next week, time is running out for Prime Minister Blair.

Those who met him had the strong impression that he was acting with No. 10′s support, and that a Democratic victory was clearly sought. Such a supposition ought to be natural, but historic ties have been jolted by the strategic and sometimes personal alliance between George W. Bush and Tony Blair over Iraq. Hain’s visit may be seen by some as diplomatic ground covering in the event of a Kerry victory.

In public the government will remain studiously neutral. And some Blairites doubt that Kerry has the campaign drive to defeat the incumbent. But in a sign of frustration inside the Labor Party at the government’s neutrality, the Blairite group Progress is to issue a scathing attack on Bush’s record, although the group is sympathetic to the action in Iraq. Alan Milburn, a former Cabinet minister, is its honorary president.

In an editorial in its journal of the same name next week, Progress says: “By his manner, his rhetoric and sometimes his actions George Bush has presented to the world an image of America that its friends know is not its true face.

“That is why those who recognize that American leadership is vital and a force for good in an uncertain world will wish John Kerry well.”

The analysis, signed off by the development secretary, Hilary Benn, concludes: “There is now a medium to high probability that there will be a lack of effective international engagement on the Middle East peace process due to other international priorities in 2004.” It says the EU has “limited influence.”

Alarm at apparent US disengagement was also signalled on Capitol Hill yesterday, as senators mulled over the peace process stalemate and sudden Palestinian disarray.

Senator Joseph Biden said the administration’s interest in galvanising peace efforts appeared to have drifted.

“The stakes are high,” Mr Biden, a Democrat, said. “Yet I don’t see a commensurate level of urgency, nor sustained and consistent involvement from the Bush administration.”

“Benign neglect punctuated by episodic engagement imperils American strategic interests in the region,” he added. “Where is American diplomacy? It is not as if we have the luxury of time.”

America’s top diplomat, Colin Powell, expressed last night a sense of impotence at the events in Gaza, saying: “We will just have to watch it unfold.” He reiterated Washington’s position that to move the peace process forward and address the current problems besetting the Palestinians, Mr Arafat needed to cede real power to a prime minister who could pick up negotiations with Israel. But he offered few new insights or initiatives.

Tony Blair has insisted that the peace process, along with Iraq, is a priority of his foreign policy and a key to winning support in the Arab world. Before the Iraq war, he told ministers and officials he was using his influence with Washington to convince the Bush administration to do more about the Middle East conflict.

But since the war, US action has been limited. Mr Blair tried to put the best gloss on the planned withdrawal from Gaza negotiated by Mr Bush and the Israeli prime minister, Ariel Sharon. He endorsed the plan, despite Palestinian condemnation, and has said the road map peace plan is not dead.

The DfID analysis says unilateral Israeli withdrawal from Gaza and parts of the West Bank not in line with the road map may lead to an increase in violence and severe poverty.

“Without action soon, there is a real danger that facts on the ground [Israeli settlement expansion and construction of a separation barrier] may make a viable two-state solution almost impossible.”

It reports a substantial risk that the Palestinian Authority will collapse, but says the most likely scenario is “continuing failure to make progress towards a political solution” leading to the “continued construction of the separation barrier, and gradual disappearance of the prospects for creating a viable Palestinian state.”

The report suggests a negotiated withdrawal by Israel could lead back to the road map and two-state solution.

But it adds: “The Palestinian state which would be left if Israel controlled all access and/ or permanently withdrew behind the current and planned route of the separation barrier would not be viable or stable.”

Last night, the UN general assembly voted to demand that Israel comply with a world court ruling and remove it. Britain backed the resolution, the US opposed it.