Cathedrals Ward Councillor Catriona Moore has been appointed as the Executive member for Social Services & Health.
Cllr Moore, Chair of Southwark Council Health & Social Care Scrutiny Sub-Committee, has been unexpectedly promoted following the resignation of Cllr Kenny Mizzi who switched from the Liberal Democrat Party to the Conservatives.
She will answer her first council question at the Council Assembly meeting on Wednesday December 4.
Cllr Moore said: "I am really excited about taking up this role. I'm particularly looking forward to working with the social services officer team and meeting social services users and clients. I wasn't expecting to be doing this job so soon but am looking forward to the challenge. I can't wait to get started."