Aled Richards-Jones said he could no longer give the role “the time and focus it deserves” alongside his job as a partner in a law firm.
The Tories seized back control of Wandsworth town hall from Labour at the local elections in May.
It was in 2022 that Labour has won control of the council for the first time since 1978.
In a statement to colleagues, Cllr Richards-Jones described the decision as “very difficult”, explaining that increasing professional responsibilities following his appointment as a law firm partner meant he could no longer devote the time the leadership role required.
“It has been an honour to serve as Group Leader for more than two years, following three years as Group Whip,” he said.
“Since I joined the partnership of a law firm last year, I have worked hard to balance increasing professional responsibilities with the demands of my political role. I felt it was right to continue leading the Group into the election and through the formation of the new administration.
“Over that time, the team into which I was recruited has achieved a level of success that has already outpaced our expectations, and as a result, my professional responsibilities have grown more quickly than expected. It is now clear to me that I can no longer give the role of Leader the time and focus it deserves alongside those responsibilities.”
