The South African Parliament voted overwhelmingly last night to disband the Scorpions, the elite crime-busting unit whose corruption investigations targeted several prominent figures of the ruling party, including Jacob Zuma, chairman of the African National Congress.

Among those who voted to close down the Scorpions as an independent unit were 40 MPs of the ANC under investigation for defrauding taxpayers of about £1.5 million with falsified travel expenses.

The Scorpions, formally known as the Directorate of Special Operations, were like the FBI and operated in close co-operation with Britain's Serious Fraud Office (SFO). They have been one of the big successes of post-apartheid South Africa. Independent from the slipshod and widely corrupt police service, into which they will now be amalgamated, they enjoyed strong public support, and their demise has sparked widespread anger.

Critics of the move say that the Scorpions are the victims of their own success. The ANC Government never anticipated that the crack crime-busters would take their constitutional independence so seriously and investigate the top ranks of the former liberation movement itself.

“The Scorpions are being killed off because they investigate too much corruption that involves ANC leaders. It is as simple and ugly as that,” Peter Bruce, editor of the influential Business Day newspaper, wrote in his weekly column.

The ANC says that the Scorpions had too little supervision from the Justice Ministry as they pursued leaders such as Mr Zuma and Jackie Selebi, the national police chief.

They have been trying since 2005 to bring to trial Mr Zuma, who was elected leader of the ANC in December, on nearly 800 charges of alleged fraud, corruption, racketeering and tax evasion in connection with the country's murky £5.2 billion arms deal with European weapons manufacturers.

That case is currently with the Supreme Court of Appeal after a series of false starts. Mr Zuma, who hopes to become President of South Africa after a general election in May, could still appear in the dock, but senior ANC sources have said that they intend to introduce legislation to grant the head of state immunity from criminal prosecution.

The Scorpions, whose top men were Scotland Yard trained, also charged Mr Selebi, a close friend of Thabo Mbeki, the former President, with corruption. The former police chief is alleged to have had a close relationship with the underworld boss Glenn Agliotti, who has been investigated for racketeering, money laundering, drug trafficking, mafia links and involvement in the murder of a mining magnate.

When he was President, Mr Mbeki suspended the Scorpions boss Vusi Pikoli for having brought charges against Mr Selebi. Mr Pikoli's successor, Mokotedi Mpshe, reinstated the charges and the police commissioner was forced to quit pending his trial.

The Scorpions pursued and pinned down thousands of complex networks of national and international corporate and public fraudsters. Drug kingpins, smugglers and racketeers felt their sting. A gang smuggling stolen platinum, South Africa's biggest foreign exchange earner, to a British smelting plant was bust as the result of a SFO-Scorpions operation.

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