The rulers of south Sudan have reached agreement with the national government that the south could secede if a majority of voters support independence in a referendum due in 2011.
This referendum was agreed in 2005 when southern rebels signed a peace deal with the ruling regime in Khartoum to end a civil war. Since then, the two sides have been in dispute over several issues, including the details of the vote.
The latest deal is likely to defuse tensions, at least temporarily. Pagan Amum, a senior southern official, told the Financial Times that the two sides had agreed that secession would require the approval of a simple majority of voters, provided that turnout reaches 60 per cent.
President Omar al-Bashir had previously insisted that the threshold should be set far higher, with a two-thirds majority needed for southern independence and a turnout of at least 75 per cent.
Khartoum has always been reluctant to let the south secede partly because the region has a large proportion of Sudan’s oil wealth.
Mr Amum, the secretary general of the Sudan People’s Liberation Movement, the former rebels who now rule the semi-autonomous south, said his party was “happy” with the outcome.
But he warned that Mr Bashir’s National Congress Party still had ample opportunity to renege on the deal.
The dispute between the two sides reached crisis point last week when Mr Amum was one of three senior SPLM officials arrested by police and detained for a few hours during a pro-democracy protest in Khartoum.
A civil war between the Arab-led north and rebels from the marginalised south began in the 1950s and became one of Africa’s longest and bloodiest conflicts.
If war restarts, it could trigger a new humanitarian crisis – an estimated 2m people died in the war from 1983-2005 – and threaten Sudan’s oil industry, in which China is a key player.
Mr Amum said the stand-off over the details of the referendum had been the result of Mr Bashir’s regime “trying to betray the people of Sudan”.
Following Sunday’s deal, a bill allowing for the referendum is due to be passed by Sudan’s parliament this week. A boycott of parliament by SPLM members is now expected to end.