The FSA says Wilson, who was appointed a director of the FSA in April 2002, has resigned for personal reasons. She will continue in her role until a replacement has been found.
As well as her TCF remit, Wilson is also a sector leader across the FSA for insurance. Previously she was director of the retail firms division and director responsible for introduction of conduct of business regulation in the mortgage and general insurance sectors.
The FSA says it is currently looking for candidates to take over the role.
A spokeswoman could not confirm if the regulator is advertising the position externally or if it is seeking to fill the position from within the FSA.
She says: “Sarah has given us a lot of notice so we have time to find a replacement. She has made a personal decision to leave the FSA. She’s not leaving to move onto anything specific initially because it’s unclear how long it will take to find a replacement.”