Eleven 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 hidden wealth of some of the world’s most prominent leaders, politicians and celebrities – including three former Tory MPs and six peers – have been revealed in the leak.
The documents show links to 72 current or former heads of state in the data, including dictators accused of looting their own countries.
They were obtained by the German newspaper Suddeutsche Zeitung and shared with the International Consortium of Investigative Journalists (ICIJ).
BBC Panorama and The Guardian are among 107 media organisations in 78 countries that have been analysing the documents.
According to The Guardian, the so-called “Panama papers” reveal that six members of the House of Lords, three former Conservative MPs and dozens of donors to UK political parties have had offshore assets.
There were also reports that a key member of Fifa’s powerful ethics committee, which is supposed to be spearheading reform at world football’s scandal-hit governing body, acted as a lawyer for individuals and companies recently charged with bribery and corruption.
The papers also reveal a suspected billion-dollar money laundering ring that was run by a Russian bank and involved close associates of president Vladimir Putin.
The operation was run by Bank Rossiya, which is subject to US and EU sanctions following Russia’s annexation of Crimea.
One leaked memo from a partner of Mossack Fonseca said: “Ninety-five per cent of our work coincidentally consists in selling vehicles to avoid taxes.”
The company has denied any wrongdoing. It says it has acted beyond reproach for 40 years and that it has had robust due diligence procedures.
The document leak comes from the records of the firm, which was founded in 1977.
The information is very recent, with the most recent records dating from December 2015.
Gerard Ryle, director of the 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.
David Cameron has promised to “sweep away” tax secrecy - but his political opponents claim little has been done.