Former head of the National Prosecuting Authority (NPA) Vusi Pikoli believes the chances of success are slim in the NPA's decision to appeal a court ruling that corruption charges against President Jacob Zuma be reinstated.

"[National Director of Public Prosecutions Shaun Abrahams ] has the right to take the decision to appeal, but the issue lies on the grounds. They look quite thin, I must confess," he said at the Big Issue's business breakfast on Wednesday.

Abrahams lodged the appeal with the Supreme Court of Appeal on Monday, citing that there was "considerable public interest" at stake in the matter.

Last month the full bench of the High Court in Pretoria ruled that Zuma should face the 783 charges of corruption.

After a seven-year battle by the Democratic Alliance, the court ruled that the decision to discontinue the prosecution against the president should be reviewed and set aside.

On April 6, 2009, then-NPA head Mokotedi Mpshe said transcripts of telephone conversations between then-Scorpions boss Leonard McCarthy and former NPA boss Bulelani Ngcuka, showed political interference in the decision to charge Zuma.

The charges were withdrawn in the High Court in Durban on April 7, 2009.

Constitutional guarantee of independence

Last month, the court found that Zuma should indeed face corruption charges after Deputy Judge President Aubrey Ledwaba said Mpshe had come under pressure and had, therefore, decided to discontinue the prosecution against Zuma.

The NPA cited six grounds for its appeal: that the court erred in finding that Mpshe had acted irrationally by not referring the complaint of abuse of process and the related allegations against McCarthy to court; there was a transgression of the separation of powers; that Mpshe did consider the merits of the case; the NPA process was abused for political reasons; that Mpshe, as acting NDPP, had the power to discontinue the prosecution; and that the court failed to appreciate the true reason for McCarthy and Ngcuka delaying serving the indictment on Zuma.

Pikoli, the current head of the Western Cape's Police Ombudsman's office, said in terms of the Constitution the NPA was independent in carrying out its functions.

"The minister of justice has the final responsibility over the NPA, but not in who to prosecute, when to prosecute, or how to prosecute.

"There is a constitutional guarantee of independence of the NPA – it does not constitute an arm of the government. It's outside of the executive. They can charge members of the executive."