
Nick Milligan, Sky Media managing director, will take sole charge of the company, prompting Curtis' departure on 31 May. There are, however, no other redundancies planned at the sales house, which employs about 300 staff.
Milligan blamed a "challenging period" for Sky Media, although he said that "in the circumstances Sky Media is doing relatively well".
BSkyB's ad revenue fell by 6% year on year over the nine months to 31 March. Although it is subscription revenue from residential pay-TV customers that drives the vast majority of BSkyB's total revenue - which totalled just under £4bn over the nine months to 31 March.
Unveiling its Q1 2009 results, BSkyB said ad revenue totalled £234m during the nine-month period, down from £248m over the same period a year earlier, reflecting, it said, a "weak advertising environment".
The News Corporation-backed group estimated in its Q1 results that overall UK TV ad spend was 12% lower over the nine months to 31 March than the same period a year earlier.