Former Army captain Doug Beattie has confirmed he will stand to become the next leader of the Ulster Unionist Party.
By Monday evening the Upper Bann MLA was the only contender in the running to replace outgoing leader Steve Aiken.
He has been widely linked to the job since Mr Aiken announced his intention to resign on Saturday.
Mr Beattie paid tribute to Mr Aiken for his courage in taking the “not easy” decision to step down.
“I am grateful for his leadership and his friendship and I am glad that he will remain both an MLA and active member of the Ulster Unionist Party,” he added in a statement which also confirmed he will run to replace Mr Aiken.
The decorated military veteran said he recognises the party and country face real challenges now and in the future.
He added he wants to present “modern, progressive” pro-union politics.
“It is not enough to sit back in defence of the union, it is time to reach out to promote the union and all its benefits,” he said.
“In doing so we can make Northern Ireland a place where people want to live regardless of identity, religion, sexual orientation or ethnicity.
“I want to build a union of people where everyone feels comfortable being who they want to be with a sense of belonging and a sense of purpose.
“I want to represent a pro-union politics that offers a modern, progressive vision for the future of the UK.
“I want to build a Northern Ireland where everyone is able to enjoy a true peace and its benefits, not just the absence of violence.”
Mr Aiken’s resignation, 10 days after DUP leader Arlene Foster was forced to quit following an internal party move against her, has thrown political unionism into further turmoil.
The announcement was prompted by mounting discontent within the party over his stewardship.
Mr Beattie and former firefighter Robbie Butler, another MLA who has been linked with a bid to be party leader, stood with Mr Aiken as he spoke to the media in Stormont on Monday morning.
But Mr Butler refused to be drawn on his intentions, instead paying tribute to Mr Aiken.
Delivering his resignation statement, South Antrim MLA Mr Aiken, a former submarine commander, said he was “aware of my limitations”.
He said: “I have taken this difficult decision because, more than ever, unionism and those in Northern Ireland who believe in the union need a clear political voice.”
He said that the UUP had delivered for the people of Northern Ireland, but added: “I am, however, self-aware enough to realise that our party, despite our strengths, is not breaking through – I am also very aware of my limitations, and despite successes over the past 19 months I realise that a change in leadership is needed.”
Mr Aiken has said he will stay in position until a successor is found.
He said there is a place for a “strong, progressive and inclusive” unionist party in Northern Ireland.
He added: “That party is the Ulster Unionist Party. Our party has delivered for the people of Northern Ireland for many years and, in the centenary of Northern Ireland, continues to do what is right – not just for unionists, but for everyone.
“If anyone doubts our credo of country over party look at how we took the health portfolio when all others avoided it – and I think we are all glad of not just our excellent health professionals, but also for the inspired leadership of Robin Swann.
“Having been in many command positions before, I know and recognise the critical point when a change is needed, for the greater good and for a reinvigoration of the fight, and that time is now.”
Ulster Unionist chairman Danny Kennedy said the change in leadership in the party would not be carried out in the same way as the DUP.
He said: “Not for us the nastiness of leadership changes carried out in dark corners like the DUP removing Arlene Foster, who frankly was deserving of better.”