Maurice Devenney has blown the Foyle Assembly election wide open by announcing his candidacy as an independent unionist.
The former DUP man launches his campaign on Wednesday for the May 5 poll.
He will be battling former DUP party colleague Gary Middleton and Ulster Unionist Julia Kee, who announced her candidacy on Monday, for a single unionist seat.
Mr Devenney, who resigned from the DUP earlier this year, said: “Following much consideration and in light of the loyal support given to me by many individuals I have decided to place myself before the electorate as an independent unionist at the impending Assembly election.
“I have been overwhelmed by the number of people who have congratulated me on my stance and offered their support.
“I will be providing an independent voice and offering to continue my lobbying and work on the ground that I already do as a councillor, albeit on a larger scale to a greater number of people.
Mr Devenney was co-opted by the DUP to Stormont in 2014 when he took over from former speaker William Hay.
He stepped down as an MLA after five months and was replaced by Mr Middleton.
“Like other unionist candidates this is the first opportunity I have had to place myself before the electorate in terms of an Assembly election.
“I have a track record of delivery which I believe stands the test of time particularly over the last 11 years of continuous service in council.
“I live in the constituency and am fully committed to improving things for the electorate of Foyle and hope to serve them for a long time to come.”
Last month, Mr Devenney said he had decided to join the UUP “after prayerful consideration”.
The situation changed dramatically just a few days later when he announced he would not be teaming up with the Ulster Unionists, claiming that there were a “number of issues that I felt we could not find agreement on”.
Mr Middleton warned that a splintered unionist vote could result in no unionist representation of Londonderry at Stormont.
“Whatever way the vote is analysed there is just over one quota available for unionists, we cannot afford to put that only unionist seat as risk,” he said.
“The upcoming Assembly election on May 5 will not only be important for the Foyle constituency but could be significant in ensuring Arlene Foster is returned as First Minister of Northern Ireland.”
Ulster Unionist leader Mike Nesbitt, who visited Londonderry on Monday, said the DUP were scaremongering.
“It’s project fear from the DUP who always say that terrible things will happen if people don’t vote for them,” he said.
“I’m fed up with project fear. In two terms at Stormont they have achieved nothing.
“I have always wanted Londonderry to have Ulster Unionist representation at Stormont and I think we have a very good candidate in Julia Kee.”
At the last Assembly election in 2011 the SDLP won three of the six seats, Sinn Fein two and William Hay took one unionist seat for the DUP.