Belardinelli (pictured) told PRWeek he left the communications team just before Christmas, although he is still working with Uber for the time being on a consultancy and advisory basis.
Belardinelli, former press secretary to ex-shadow chancellor Ed Balls, joined Uber in 2015, initially as head of comms for the UK and Ireland.
He was promoted to Northern & Eastern Europe comms chief last year, prior to the appointment of Lottie Dominiczak as head of communications for the UK.
Belardinelli's role has not yet been replaced.
In recent months Uber has been taking steps to rebuild its reputation in the UK and elsewhere over accusations around safety and the rights of drivers.
In June last year the company was granted a short-term licence to operate in London - Transport for London had earlier refused to renew the licence, saying Uber was not a "fit and proper" operator. Uber subsequently made changes, including reporting crimes directly to the police instead of logging criminal complaints with TfL. It also added limits to driver working hours.
In October, Uber launched a series of safety features in the UK and elsewhere in Europe, including a new ‘safety centre’ where passengers and drivers can share trip details with friends and family.
Last month, the Court of Appeal upheld a ruling that stated Uber drivers are workers and should receive entitlements such as holiday pay and the national minimum wage.
In recent days the company has received coverage for its partnership with meditation app Calm, which lets passengers access guided meditation exercises timed to the length of an average trip.