Basil McCrea, who once stood for the leadership of the UUP, announced his resignation from the party on Friday morning.
Just hours after South Down MLA John McCaliister announced he was to leave the party, his colleague Lagan Valley MLA McCrea said he was to leave too.
And Mr McCrea said forming a new party with John McCallister is “the top option” at the minute.
In a direct attack on his former party leader Mr McCrea said: “I have no confidence in what Mike Nesbitt says.”
He added that the “There is no future for me in the UUP”, and accused the UUP of “getting into bed with the DUP”.
On Thursday night the DUP and UUP chose joint Unionist candidate Nigel Lutton to stand in the Mid Ulster by-election.
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