President Thabo Mbeki filed papers in the Constitutional Court on Monday to join an application for leave to appeal against a Pietermaritzburg High Court judgment on Jacob Zuma.

Presidential spokesman Mukoni Ratshitanga told Sapa papers had also been filed by the cabinet to be part of such an application.

He said Mbeki had filed in both his personal capacity and as head of the executive.

In the recent Pietermaritzburg High Court ruling, Judge Chris Nicholson found the executive might have interfered in the decision to prosecute the African National Congress president.

"I am... not convinced that the applicant (Zuma) was incorrect in averring political meddling in his prosecution," Nicholson noted in finding the prosecution of Zuma invalid.

Nicholson criticised former justice minister Penuell Maduna's involvement with former national director of public prosecutions Bulelani Ngcuka early in the investigation.

He found it startling that Ngcuka had thanked Maduna for his support at a press conference, given the independence of the NDPP.

It was after the court ruling that the ANC announced it was
recalling Mbeki not to punish him, but as "a political way to deal with the implications of Judge Nicholson's ruling".

However, announcing his resignation on Saturday, Mbeki disputed suggestions of his involvement in a political conspiracy against Zuma.

"I would like to state this categorically: that we have never done this and never compromised the right of the National Prosecuting Authority to decide whom it should prosecute and not prosecute," Mbeki said.

Hinting on Monday that ANC deputy president Kgalema Motlanthe could become caretaker president, Zuma said "there is no fight" between him and Mbeki.

In his 30 years with the ANC, Mbeki had been more than a comrade, he had been a friend and a brother, Zuma said. "We have undertaken many tasks together".

People misunderstood the democratic process within the ANC. When there was a contest, the media said there was a fight, Zuma said, referring to the battle he waged against Mbeki for the ANC presidency last year.

He, however, said the ANC "... would like to underline that we acknowledge and accept the ruling of Justice Chris Nicholson and reiterate that we will, as always, abide by the decisions of this and all courts in our country."

After Nicholson's September 12 judgment, the government said Mbeki and the Cabinet were seeking legal advice on his political interference comments.

"Cabinet respects the judiciary and its decisions," government spokesman Themba Maseko said at the time.

"However, Cabinet does not accept the suggestion that either the president or the executive interfered with the prosecuting decisions of the National Prosecuting Authority (NPA) regarding the prosecution of any person or persons," he said.

The "untested inference" that there was political interference with the prosecuting decisions of the NPA in this, or any other case, was untrue, unfounded, and "does not hold water", he said.

This did not mean Cabinet rejected Nicholson's judgment.

The legal opinion sought would be only on how the inference made could be corrected.

Essentially, Cabinet wanted the comments removed from the judgment, which was a public record.

"The judge may not have had all the facts in front of him when he reached that conclusion," said Maseko.

The NPA has already said it intends appealing against the decision.

Nicholson found that, in terms of the law, Zuma should have been allowed to make representations to the NPA when it decided to make an about-turn on a previous public statement that he would not be charged.

The NPA said it had studied Nicholson's judgment and had taken legal advice and consequently had "decided to apply for leave to appeal against the judgment".

The NPA said the grounds for appeal would include:
-- the contention that the court was incorrect in its interpretation of the constitution and the NPA Act regarding the obligation to solicit representations before recharging; and
-- that the judgment had made some serious legal findings impacting on the operational processes in the NPA.

Zuma had faced a charge each of racketeering and money laundering, two charges of corruption and 12 charges of fraud related to the multi-billion rand government arms deal.

He was charged in 2005, but that case was struck from the roll in 2006. He was re-charged in December 2007.

Also likely to fall away were a charge of racketeering and two counts of corruption faced by two Thint companies -- Thint Holding (Southern Africa) Pty Ltd and Thint (Pty) Ltd -- the South African subsidiaries of the French arms manufacturer Thales International (formerly Thomson-CFS).