South Africa has blamed Britain for the deepening crisis in Zimbabwe by accusing the UK of leading a campaign to "strangle" the beleaguered African state's economy and saying it has a "death wish" against a negotiated settlement that might leave Robert Mugabe's Zanu-PF in power.

According to a South African government document circulating among diplomats ahead of a regional summit this week, President Thabo Mbeki will paint an optimistic picture of his efforts to broker an agreement between Mr Mugabe and the Zimbabwean opposition.

But the document, a draft of the report the South African president is expected to present at the meeting, says Britain remains a significant obstacle by spearheading sanctions that Mr Mugabe blames for his country's economic collapse.

"The most worrisome thing is that the UK continues to deny its role as the principal protagonist in the Zimbabwean issue and is persisting with its activities to isolate Zimbabwe," the report says.

"None of the western countries that have imposed the sanctions that are strangling Zimbabwe's economy have shown any willingness to lift them."

Britain pressed the European Union to impose "targeted sanctions" against Zimbabwe's leadership by refusing visas, freezing bank accounts and other measures that the UK said were aimed at individuals without harming Zimbabweans.

But Mr Mugabe has blamed what he describes as the "illegal sanctions" for the economic collapse and said his government is a victim of British imperialism because it seized white-owned farms for redistribution to poor blacks.

His opponents say the crisis is the result of a brutal strategy to hold on to power by violently suppressing the opposition, rigging elections and trying to buy support by seizing the farms. This last move devastated the tobacco export industry that provided Zimbabwe with much of its foreign earnings.

The wholesale printing of money helped fuel inflation now estimated to be running at about 20,000%. Shops are virtually empty of basic foodstuffs.

Some African leaders have been willing to criticise Mr Mugabe, although a Zambian opposition leader, Michael Sata, urged the region's leaders to "join hands and launch strong protests against attempts by the west to recolonise Zimbabwe".

The South African report describes the crisis as "Zimbabwe's bilateral dispute with Britain". However, the focus of Mr Mbeki's efforts is to reach an agreement between Mr Mugabe and the opposition Movement for Democratic Change ahead of elections next year.

Mr Mbeki has not had a smooth ride. Mr Mugabe's two negotiators, both cabinet ministers, failed to arrive for talks in South Africa last month. The ministers, Nicholas Goche and Patrick Chinamasa, finally arrived in Pretoria a week ago.

The document says some issues, including constitutional reforms, have been "worked out". "There are strong indications that the two sides are sliding towards an agreement," it says.

But MDC sources say that agreement is not near and they suspect that Mr Mugabe is playing for time until the end of the year when the focus will shift to the presidential election campaign. Meanwhile, the economic crisis is expected to deepen. More than 3 million Zimbabweans have left the country in search of work.