Peter Smith, head of investment policy at the Financial Services Authority (FSA), is leaving the regulator.
The FSA confirmed Smith's departure but would not say when he is leaving, but a source said it would be within "three or four" weeks.
Smith, who has been at the regulator for over a decade after joining in 1999, will become director of policy at the Dubai regulator.
He is the latest senior member of the FSA's policy team to announce his exit.
Smith was heavily involved in the Retail Distribution Review and the regulator's work on tackling failing investment schemes.
The FSA is yet to announce a replacement.
Despite improved risk appetite
FOS award limit increase
Relates to 136 million transaction reports
Ceremony will take place 13 November