The big divide in the Shiv Sena has now trickled down to the lower rungs of the party with 66 of 67 Sena members in the Thane civic body siding with the faction headed by new Chief Minister Eknath Shinde.
Uddhav Thackeray appears to have lost his hold over the civic body even before its elections, due later this year.
This is the latest blow for Uddhav Thackeray, who had to quit as Chief Minister last month after most Sena MLAs backed Mr Shinde's rebellion.
Thane is the stronghold of Mr Shinde. Thane's civic body is the most important in Maharashtra after Mumbai's Brihanmumbai Municipal Corporation (BMC).
The Thane Municipal Corporation was dissolved a while ago but elections have been delayed. The councillors met the Chief Minister last evening and joined his faction.
Uddhav Thackeray is fighting to retain control of the party founded by his father Balasaheb Thackeray.
The Shinde faction has claimed Balasaheb's legacy as their own and is angling for the control of the party. In the assembly and the Supreme Court, they have declared that they are the real Sena, since they have the support of more than two-thirds of the party MLAs.
In the test of strength in the Maharashtra assembly earlier this week, 40 of Sena's 55 MLAs sided with the Shinde faction.
But gaining actual control of the party also involves gaining grassroot level support -- from the cadres, local leaders and corporators. If the party officially splits, the final call on who gets the name and election symbol can only be taken by the Election Commission.
The Thane Sena leaders' switch is also seen as a pay-off for the BJP strategy of giving the top job to Eknath Shinde instead of its two-time Chief Minister Devendra Fadnavis. Party insiders had indicated that it might draw the support of the Sena rank and file to the Shinde camp.
The Thackeray faction is fighting back, appointing a new Chief Whip for its 19 members in the Lok Sabha. The party also has three MPs in the Rajya Sabha. It has written to the Election Commission in a bid to block the handover of the name and election symbol.