Why oil is critical in preventing a return to war in Sudan

But since the signing, the Southerners’ confidence in the peace deal has been severely tested by delays and disputes over its implementation, which many perceive as a deliberate tactic of the Northerners.

The demarcation of the North-South border is still unresolved.

Elections originally scheduled for half way through the transitional period are now planned for April, just months before the referendum, and there are fears they may be delayed further.

The violence continues and armies are massing on either side of the border.

A recent report by Oxfam and others noted that last year, 2,500 more people were killed in the South, compared with the troubled Darfur region.

It seems a return to the conflict that claimed two million lives and displaced more than four in five southerners is all too possible.

Dr Rosie Sharpe works for Global Witness. E-mail mail@globalwitness.org