LONDON ( AFP ) ― WikiLeaks founder Julian Assange vowed to publish secret details of offshore accounts after a Swiss banking whistleblower handed over data Monday on 2 , 000 purportedly tax - dodging individuals and firms . Former Swiss banker Rudolf Elmer , who worked for eight years in the Cayman Islands , a renowned offshore tax haven in the Caribbean , personally gave Assange two CDs of data at a London press conference . Elmer said he wanted the world to know the truth about money concealed in offshore accounts and the systems in place to keep it secret . He handed over the data at the Frontline Club -- WikiLeaks ’ British HQ -- as Assange put in a rare appearance away from the remote country house of the club ’ s founder , where he has been bailed to live while he awaits extradition proceedings . “ I am here today to support him , ” Assange told reporters . “ He is a whistleblower and he has important things to say . ” The Australian promised “ full revelation ” of the data but said it would be weeks before any of the information could be checked and published by the WikiLeaks website . WikiLeaks founder Julian Assange ( left ) is given two CDs by former Swiss banker Rudolf Elmer following a press conference in London on Monday . ( AFP - Yonhap News ) Elmer declined to give the names of those on the CDs or say how many individuals were involved , though he mentioned the 2 , 000 figure in British newspaper The Observer , which published an interview with him Sunday . He has said the information includes details on around 40 politicians , multinational companies and financial institutions from the U . S . , Europe and Asia all secretly avoiding paying tax . “ The only hope I have is to get society to know what ’ s going on , ” he said . “ I have been there , I have done the job , I know what the day - to - day business is , I know how much is documented there and how much is not . ” I am against the system . I know how the system works . I want to let society know how this system works because it ’ s damaging our society . “ We ’ re going to talk about the system and that ’ s why I ’ m here . “ The money is hiding in offshore banking secret jurisdictions . ” He said he was offered money for his silence and that he offered the information to former German finance minister Peer Steinbrueck for free but had received no response . Assange said WikiLeaks has so far released 2 . 3 percent of the 250 , 000 U . S . diplomatic cables and was struggling with the volume of data . The Australian is on bail in Britain awaiting Sweden ’ s attempt to extradite him for questioning on sexual assault allegations . A full extradition hearing will be heard at a London court on Feb . 7 - 8 . Elmer was dismissed in 2002 after eight years as the chief operating officer of Julius Baer Bank in the Cayman Islands . He is to appear before a Zurich court on Wednesday to answer to charges of bank secrecy violations , after he passed on clients ’ data to WikiLeaks in 2007 . The move led to tax evasion prosecutions in several countries against these clients . In 2008 a former employee of Liechtenstein ’ s biggest bank sold data on client accounts in the secretive Alpine banking haven to the German secret service for five million euros . And last year officials in the German state of North Rhine - Westphalia bought a computer disc for a reported 2 . 5 million euros with information on secret Swiss accounts . As a result German tax authorities recovered 1 . 6 billion euros in 2010 from holders of the accounts , according to the weekly Der Spiegel .