William Hill said the decision to merge the two divisions had been made in order to focus on recovery in 2021, which could feature a packed sporting programme including the rescheduled Uefa European Championship.
It is the latest major reorganisation at William Hill, who closed 713 betting shops last autumn in response to the government's crackdown on FOBTs.
A number of senior figures have also left the bookmaker, the latest set to be Frampton who joined Hills in 2010 and became director of UK retail in 2014.
Walker and Frampton will however work together during a six-month transition period.
Bengtsson said: "We will be immensely sad to say goodbye to Nicola Frampton when the time comes. Nicola has been with William Hill for ten years and has been a driving force on the executive team as well as being instrumental in reshaping and transforming our retail business."