The FSA today confirmed the departure of head of supervision Jon Pain.
Board member Pain will leave the organisation in 2011.
His departure follows that of the FSA's managing director of risk, Sally Dewar, who earlier this month announced she would also leave in May 2011.
Hector Sants says: "Following the announcement that the FSA will be split in 2012, Jon Pain has decided that there will not be a suitable role for him in the new structure. So, it is with regret that I have to announce that Jon has decided to leave the FSA next year.
"However, he has agreed to carry on as managing director of supervision until the switch over to the new structure within the FSA, which we hope to achieve in January 2011."
The coalition Government plans to scrap the FSA and fold many of its powers into a new Bank of England subsidiary.
Its remaining powers will be divided up between a new Consumer Protection and Markets Authority, and a new financial crime agency.
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