The DA campaign to wrestle control of the Gauteng provincial government has been dealt a major blow.

Former Johannesburg mayor Dr Mpho Phalatse has resigned as a DA councillor and plans to significantly reduce her involvement in politics.

Phalatse is the most influential leader to step back from party responsibilities since ActionSA leader Herman Mashaba left the party.

Although she has not yet announced a full resignation from party membership, Phalatse is understood to be on her way out.

Phalatse sent her resignation letter to council speaker Colleen Makhubela on Monday and will be leaving the city on 30 September.

For months now it has been speculated that Phalatse is likely to join her husband Brutus Malada at ActionSA.

This follows a series of encounters with the top leadership of the DA which cost her the mayoral chain in Johannesburg.

After the 2021 elections ended with no party securing a clear majority in Johannesburg, it was Phalatse who united opposition parties and formed a government for the R80-billion city.

She lost that coalition when DA federal chairperson Helen Zille decided the party could no longer work with the EFF.

Things immediately went pear-shaped for her in the DA and she later lost her campaign for leader of the DA to Zille's blue-eyed boy John Steenhuisen.

With the DA now unlikely to recapture the City of Jo'burg, Phalatse was unlikely to return as mayor.

She was also not being considered for the position of DA premier candidate for Gauteng after the 2024 elections.

In the council, Phalatse is credited with developing the only credible blueprint for reducing the impact of load shedding on the local economy.

And the last time Johannesburg was stable, Phalatse was the major. Since leaving office, the city has been led by two "puppet mayors" from Al Jama-ah, a party that received less than 1% of the votes from the residents of Johannesburg.