Johannesburg Mayor, Herman Mashaba, has resigned in protest at the election of former DA leader Helen Zille, to a top party position.
Zille took over the role as the party's Chairperson of the Federal Council, beating off three other contenders including the DA's Nelson Mandela Bay caucus leader, Athol Trollip.
Announcing his resignation at a media briefing in Johannesburg on Monday, Mashaba said the DA was no longer aligned with his views.
He says the events of the past few months, particularly this weekend prompted him to choose between the party and his country.
DA Leader, Mmsusi Maimane, says he considers Mashaba as a friend and comrade, adding that Johannesburg is a better place today than under the ANC.
His resignation is effective from the end of November.