Sheffield councillor Jack Scott has been suspended from the Labour group and lost his seat on the council’s senior leadership team, it is understood.
Coun Jack Scott is no longer a Cabinet member but it’s unclear whether it was his decision to leave.
He has declined to comment.
The Labour group said it would be issuing a statement shortly.
Coun Scott was Cabinet member for transport and development and was in charge of some of the biggest issues in the city including new homes, transport, development, climate change and air quality.
He led on a wide range of issues including creating more affordable homes, HS2, fracking, climate change, parking and plans for a controversial pollution charge.
Over the past six years he has held Cabinet portfolios for environment, recycling and streetscene, community services, transport and sustainability.
He will remain as a Labour councillor for Arbourthorne where his term of office is until 2022.