The Directorate of Special Operations (the Scorpions), began operating on January 12 2001.

Launched by President Thabo Mbeki in the wake of widespread public perception that crime was out of hand, it was tasked with securing convictions in the areas of white collar and organised crime. But, despite the unit claiming a 90% success rate, it has never been plain sailing.

The first storm broke in 2003 when Ngcuka's office pursued corruption allegations against Deputy President Jacob Zuma.

And despite Ngcuka's initial successes in bringing prominent politicians and businessmen such as Billy Rautenbach and Tony Yengeni to justice, he was not prepared for the onslaught he would encounter from political heavyweights in the arms deal probe.

Pressure on Ngcuka started to mount soon after the Scorpions launched a probe into Zuma and then into deposits made into the bank account of former Transport Minister Mac Maharaj. Both investigations involved Durban businessman Schabir Shaik.

Shaik's brother Mo, and Maharaj alleged that Ngcuka had been an apartheid spy and the subsequent furore led to an investigation by Judge Joos Hefer.

Although Hefer found no evidence to substantiate the claims, Ngcuka resigned in May last year, citing the government's lack of support over a report by Public Protector Lawrence Mushwana.

Mushwana found that Ngcuka had impugned Zuma's dignity by telling the media he had a prima facie case against Zuma which he did not think he could win.

Mushwana also investigated two other complaints, one of malicious prosecution by mining magnate Brett Kebble and his father Roger Kebble, and the other by former City Press editor Vusi Mona, that Ngcuka had leaked information about Maharaj during an off-the-record meeting with black newspaper editors.

At the same time the Scorpions found themselves accused by the police of picking cases only where there was a guarantee of success.

Ngcuka's decision to leave triggered a flood of resignations within the National Prosecuting Authority and the Scorpions.

With acknowledgement to the Sunday Times.