YET another South African chief of police and two ministers have bitten the dust in the latest swirl of corruption scandals to hit President Jacob Zuma's government. An array of other politicians—bosses of state-owned companies, intelligence chiefs and directors of government departments—are also fighting for their professional lives over allegations of tender fraud and other irregularities. Even Mr Zuma could find himself back in trouble if the supposedly independent inquiry he has at last agreed to establish into a notorious arms deal worth $5 billion in 1999 is given a free rein.

The Special Investigating Unit (SIU), set up to deal with graft and organised crime, reckons that as much as 20-25% of state procurement expenditure, amounting to around 30 billion rand ($3.8 billion) a year, is wasted through overpayment and corruption. The unit, which comes under the independent national prosecutor's office, is probing dodgy deals worth 12 billion rand. An investigation of the ministry of public works, one of the biggest-spending government departments, revealed 3 billion rands' worth of improperly awarded tenders. The auditor-general said that 26 billion rand has been wasted or spent “irregularly” in the past year. A third of government departments have awarded contracts to officials and close family members, it was reckoned.

An audit of the Social Security Agency, which doles out some 100 billion rand a year to 15m South Africans, almost a third of the total population, shows its finances to be in chaos and riddled with fraud. A recent study reckons that 7% of social benefits are obtained illegally. More than 15,000 fraudulent beneficiaries have been convicted in the past five years but that is the tip of the iceberg. The agency's financial director was fired in July.

A remarkably high proportion of officials now seem to be at it. Just within the past few months the head of the state-owned Passenger Rail Agency's corporate real-estate department has been “placed on special leave” after the discovery of “widespread fraud”. The director of the state language board has been fired for “financial mismanagement”. The financial boss of the state communications regulator has been sent on “gardening leave” after the revelation of “financial irregularities”. The head of the police's crime intelligence division has been suspended after being accused of using witness-protection funds to pay for salaries, houses and cars for family and girlfriends; investigations are continuing. The mayor of Pretoria, the capital, is under investigation for alleged nepotism, corruption and mismanagement. The SIU says the debt-ridden South African Broadcasting Corporation is “rotten” right to the top. The chief executive of the South African Post Office has been given “leave of absence pending the outcome of hearings” into corruption. And on it goes.

In a report this month Thuli Madonsela, the ombudsman, found Sicelo Shiceka, the local-government minister, guilty of fraudulent conduct after spending more than 1m rand of public money on private first-class air travel and sojourns at five-star hotels. Half of that he reportedly splurged on visiting a convicted drug-dealing girlfriend in prison in Switzerland, after claiming he was there on official business. After Ms Madonsela urged Mr Zuma to take “serious action” against Mr Shiceka, who has been on “sick leave” for the past eight months, the minister finally got the chop.

For several weeks, the president had refused to issue a public comment on the Shiceka case or on the ombudsman's two equally damning earlier reports on Bheki Cele, the chief of police, and Gwen Mahlangu-Nkabinde, the public-works minister. Both had been accused of unlawful conduct over the lease of new police headquarters at grossly inflated prices; both deny the charges. Though Mr Zuma has repeatedly professed his eagerness to eradicate public-sector sleaze, setting up a plethora of anti-corruption bodies and authorising no fewer than 18 SIU investigations into government departments and other public entities, he has been markedly more reluctant to act against political bigwigs and friends.

But pressure on him to sack the two ministers eventually proved irresistible. Mr Cele has now been suspended pending an independent investigation. Jackie Selebi, Mr Cele's predecessor, was sacked as police chief two years ago after being accused of corruption. He was sentenced last year to 15 years in jail but has appealed.

Of potentially much greater significance is Mr Zuma's recent announcement, following more than a decade of demands for an independent inquiry into the arms deal, that he would finally set one up. The original accusations concerned the purchase of helicopters, submarines, corvettes and fighter aircraft for South Africa's defence forces from various European companies.

It could reopen a whole can of worms for the ruling African National Congress (ANC) and embarrass Mr Zuma himself. So far, only two people have been convicted over the scandal, one of them Schabir Shaik, Mr Zuma's former personal financial adviser and benefactor. He was sentenced to 15 years in jail in 2005 after being found guilty of soliciting bribes on Mr Zuma's behalf from arms manufacturers, prompting the then president, Thabo Mbeki, to sack Mr Zuma as his deputy. Later charged with corruption, Mr Zuma successfully argued that the charges should be dropped on a legal technicality just before his election as president (by the ANC-dominated parliament) in May 2009.

To his critics' surprise, Mr Zuma has now appointed a respected appeal-court judge, Willie Sereti, to head the arms-deal inquiry. He will be assisted by two other senior judges. There were concerns that Mr Zuma might seek to protect himself and his friends by limiting the commission's powers. But this does not seem to have been the case.

Under broad-ranging terms of reference announced on October 27th, the commission is to examine whether anyone, inside or outside the government, “improperly influenced” any of the arms-deal contracts and, if so, whether legal proceedings should be brought against them. It will have powers of search and seizure, to subpoena witnesses and to compel them to answer questions. Anyone who refuses to do so could face up to a year in jail. It has a budget of 40m rand and must complete its work within two years. This is generally deemed a good beginning.

Note: An earlier version of this article appeared online on October 20th and some copies of the print edition dated October 22nd. It was updated on October 27th.