Keydata founder Steward Ford is seeking to ban FSA staff who saw protected attorney-client e-mails from being involved in an investigation into the company.
In October, Ford won a landmark High Court judgement against the FSA, which was found to have acted unlawfully in its use of the legally-privileged emails in its enforcement investigation.
At a hearing yesterday, Ford told a judge the FSA should now exclude from its investigation anyone who saw the emails, Bloomberg reports.
He also wants the regulator to hand over any communications with other agencies to which it sent the material, including the Serious Fraud Office and the Insolvency Service in Britain and financial watchdogs in Luxembourg and the Cayman Islands.
Hodge Malek, one of Ford's lawyers, said: "We want to know who at the FSA has seen the material. We say those people should be taken off the case."
He also said the distribution of the emails to other agencies showed the FSA was "hell-bent" on bringing Ford down.
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