Johannesburg - A phone call by Judge Willem Heath to former President Nelson Mandela was behind President Thabo Mbeki's angry public attack on the judge on Friday, the Sunday Times reported.

Mbeki announced on Friday that the Heath Special Investigating Unit would play no role in the probe into alleged corruption in the R43-billion arms deal and that he would be replaced as soon as Parliament reconvened next month.

Heath called Mandela on Thursday, asking him for a "testimonial". Mandela is said to have agreed to write a reference for him, but became suspicious when Heath asked him instead to testify to his abilities by phone to all who called. Mandela then informed a furious Mbeki of the judge's call.

A senior government official said: "Madiba believed that he was being set up and that those who were going to call were media people. Heath wanted Madiba to be critical of what the government was saying. That's why Madiba had to inform the President," the Sunday Times was told.

Heath on Saturday confirmed that he had called Mandela to ask if he could use him as a reference as he was looking for a new job. He said he was "amazed" that Mbeki knew about the conversation. "I did speak to Mr Mandela and we agreed that the discussion would remain between us. But even if I asked Mr Mandela for a testimonial, why should [Mbeki] be angry? If I had to ask him for one, what would he say?"

Two of Mbeki's close advisers said the President was so incensed at Heath's call that he urgently discussed the issue with the Minister of Justice, Penuell Maduna, and decided to publicly censure Heath and expedite his removal from the unit.

According to the Sunday Times, the already furious, Mbeki then received copies of four "organograms" - detailed diagrams - from intelligence agents. The organograms linked him, Mandela, Deputy President Jacob Zuma, the Minister in the Presidency, Essop Pahad, and the former Minister of Defence, Joe Modise, to various companies involved in the deal.

During a televised address, Mbeki displayed two of the organograms, which he said were part of Heath's alleged incriminating documents.

Heath on Saturday denied that his unit had drawn up the diagrams. He said he had never set out to prove that Mbeki or Mandela had been involved in any corruption regarding the arms deal.

Despite the public rebuke by the President, Heath has refused to go quietly. He said on Saturday that Mbeki had been "wrongly advised" about excluding his unit from the arms probe. The government had a "complete misconception" of the issue when it claimed that there was no prima facie evidence of any criminal wrongdoing, he said.

Mandela's spokesperson Zelda la Grange was unavailable for comment on Saturday, the Sunday Times said.

With acknowledgment to News24.