Cllr Warren Morgan, former Brighton and Hove City Council leader, announced on Friday (February 22) that he was leaving the Labour Party after 27 years.
He blamed 'Brexit, antisemitism and the toxic culture of aggression and bullying within the Party'.Today (February 25), he said: "This morning, with Cllr Michael Inkpin-Leissner, I formally constituted @TheIndGroup on @BrightonHoveCC - possibly the first foothold in local government for the new group established in Parliament a week ago."
Cllr Morgan, who represents East Brighton, is set to stand down as a councillor in May, but said he 'would not rule out' standing for election again.
He said: "The Independent Group, not being a Party, can't endorse candidates in elections and there is very little time for that to change before nominations close in mid-April.
"I wouldn't want to run on any slate against former colleagues and friends of mine in Labour, but we are in a period of rapid political change so won't rule anything out.
"I do feel like I have something to offer public life still, but how I do that is uncertain at this point."
He is joined by Cllr Inkpin-Leissner, who has been sitting on the council as an independent councillor since he left the Labour Party in March 2017, citing Corbyn and Brexit.
Nationally, TIG formed last week and is a pro-EU political grouping of MPs who have left Labour and the Conservative Party. They include Chuka Umunna and Anna Soubry.
Cllr Morgan added: "I have made it clear that we will vote with the @bhlabour Administration in this week's Budget and any other votes that arise. The balance of power rests with @BHGreens councillors in blocking or supporting any Conservative takeover."
This comes after another Labour councillor crossed the floor and joined the Conservative Party last week.
It means the Tories have 21 councillors while Labour – after Cllr Morgan's departure – now has 19.
There are also 11 Green councillors, two TIG councillors and one vacancy – formerly Labour.
The Greens could hold the balance of power in a vote on the new administration, which is expected to take place on March 5 – after a crucial Budget meeting on Thursday (February 28).