The names of three former African leaders feature prominently in what is generally believed to be the biggest financial data leak in history. They are Egypt’s former president Hosni Mubarak, Libya’s late leader Muammar Gaddafi and one-time president of Sudan Ahmad Ali al-Mirghani.

The data contains secret offshore companies linked to the families and associates of Mubarak, Gaddafi, Ali al-Mirghani and Syria’s President Bashar al-Assad.

The huge leak of confidential documents known as the Panama papers reveals how the rich and powerful use tax havens to hide their wealth.

The scandal blew open when 11 million documents were leaked from one of the world’s most secretive companies, Panamanian law firm Mossack Fonseca.

They show how Mossack Fonseca has helped clients launder money, dodge sanctions and evade tax.

The company says it has operated beyond reproach for 40 years and has never been charged with criminal wrong-doing.

The documents show 12 current or former heads of state and 61 people linked to current or former world leaders in the data. They include the Icelandic Prime Minister, Sigmundur Gunnlaugson, who had an undeclared interest linked to his wife's wealth and is now facing calls for his resignation.

The files also reveal a suspected billion-dollar money laundering ring involving close associates of Russian President Vladimir Putin.

Gerard Ryle, director of the International Consortium of Investigative Journalists (ICIJ), said the documents covered the day-to-day business at Mossack Fonseca over the past 40 years.

“I think the leak will prove to be probably the biggest blow the offshore world has ever taken because of the extent of the documents,” he said.

The documents also shed light on how Mossack Fonseca offered financial services designed to help business clients hide their wealth.

•Based on foreign media reports.

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