NI21 councillor, Johnny McCarthy has announced he has quit the party.
The Lisburn and Castlereagh representative was the only elected member of the party following last year's council elections.
He was the party's deputy leader.
Johnny McCarthy's election victory came hours after the party imploded just ahead of polling opening.
Senior members, the party chair Tina McKenzie and founding member and ex-UUP MLA John McCallister announced their decision to quit.
Mr McCarthy's election in Lisburn was the party's only electoral success despite targeting several seats.
This morning he announced he was leaving NI21.
He said he would remain as an an independent councillor until the end of his term, but has not made any further decisions after that.
The party continues under the leadership of MLA Basil McCrea.