MP Lee Scott has stood down from his role as parliamentary private secretary (PPS) to Justice Secretary and Lord Chancellor, Chris Grayling.
Ilford North MP Mr Scott, 58, said he has resigned after being offered a new, unspecified position.
His office said details of the new role should emerge in the "next few weeks".
The Conservative MP had worked for the justice secretary since the cabinet reshuffle in September 2012.
Ilford North is set to be a heavily contested seat in next year’s general election after Labour won power from the Conservative/Liberal Democrat coalition in May.
Mr Scott has been Conservative member for Ilford North since 2005 and won the last election with 45.74% of the vote.