Up to nine women have made allegations of inappropriate sexual activity against Basil McCrea, it can be revealed.
The revelation that there are multiple allegations against the beleaguered NI21 leader will further rock the party, which is teetering on the brink of collapse following a disastrous week.
Mr McCrea, who confirmed that the allegations against him were sexual in nature in an email to party staff this week, has strongly denied any wrongdoing.
NI21 suffered another damaging day yesterday, performing disappointingly in local council elections.
Its European candidate Tina McKenzie, who resigned from the party's executive this week, said it will be difficult for Mr McCrea and John McCallister to remain as leader and deputy leader given the current crisis.
Last night one of the women who has made allegations went public with her story.
Former party worker Ashleigh Murray (23) told the BBC: "He is a respected politician with a lot of power. Who was going to believe me?"
Asked why she continued to work for the party, she said: "I needed the work, I left school with no qualifications."
Last night deputy leader Mr McCallister said Mr McCrea must now step aside while the investigation is being carried out.
"In light of the fact that a young woman has now publicly come forward regarding the allegations against Basil McCrea, I am now compelled to ask him to immediately step aside from the leadership of NI21 for the duration of the investigation.
"It would be impossible for the leader of any political party to remain in post when confronted with an investigation into such serious allegations."
Party sources revealed that Mr McCrea, who is fighting for his political career, is facing a series of allegations. This was also confirmed by his deputy.
Mr McCallister initiated an investigation by independent counselling group Carecall, after hearing rumours about Mr McCrea earlier this month.
Mr McCrea and he resigned from the Ulster Unionist Party in February of last year.
They fell out publicly this week after Mr McCallister denounced a decision by the party executive to redesignate from 'unionist' to 'other' as "crazy".
He told the Belfast Telegraph: "I am concerned that some complaints may extend back to the Ulster Unionist Party, but I don't know that for a fact. Carecall took a significant number of statements last Friday. As far as I know they have taken more today. I would hope they would be in a position to put these allegations to Basil early next week, perhaps Monday or Tuesday."
He went on: "The allegations will then be put to Basil and he will have 48 hours to consider them before they meet him, receive his response and compile a final report, which will be given to me and to the Assembly Commission at Stormont."
Mr McCallister stressed that he had no control over the investigation and would have no direct input.
"This must be thoroughly, independently and robustly investigated. Then it will either exonerate Basil, or there will be recommendations coming from it and they will have to be considered," he said.
"I was initially made aware of the allegations or rumours from two sources. Jon Rainey was one, and I had a separate source in the constituency," said Mr McCallister, an MLA in South Down.
Jonathan Rainey is NI21's former director of communications, now a political consultant.
The rumours gained more currency last week when Mr McCrea sent him a solicitor's letter accusing him of hinting at misconduct in a series of cryptic tweets and internet posts.
Mr Rainey denied this, and Mr McCrea withdrew the threat.
Some questioned whether Mr McCallister was wise to initiate an inquiry during an election campaign. He stated: "Once I became aware of these rumours a duty of care to staff came into play and I had to act."
After that, a woman contacted the media with a specific complaint about Mr McCrea. Mr McCallister met with her.
One of her allegations involved an incident which was said to have occurred during a planning get-together held in a hotel near Belfast in early April 2013, two months prior to the launch of NI21.
"She made allegations which amounted to sexual harassment and bullying in the workplace," Mr McCallister said.
The Carecall investigation was originally due to start yesterday, the day after the election.
After hearing the allegations, Mr McCrea asked the organisation to move the start date forward to May 16.
Mr McCrea has consistently denied any wrongdoing.
Yesterday the Belfast Telegraph sent him a series of questions about the number of complainants and put one woman's name to him.
He replied: "I am not aware of any outworkings of the Carecall investigation. I have not been involved in that. I am aware of one unsubstantiated allegation and I am considering how to address it."
Asked whether it was true that his partner had taken the publicity badly and he was now living away from home, Mr McCrea said: "I am not going to talk about that."
NI21 was set up last June by Basil McCrea and John McCallister, two former UUP MLAs. It promised non-sectarian pro-Union politics. This week descended into chaos after its executive proposed dropping its unionist designation at Stormont. It then emerged he had initiated an inquiry into claims of inappropriate sexual activity involving female party workers.
Timeline of a political implosion
- A snap decision by NI21 to change its designation at Stormont from 'unionist' to 'other' a day before polling stations across Northern Ireland open causes controversy.
- The decision leads to party deputy leader John McCallister speaking out and calling the party "dysfunctional" – claiming that he was never consulted about the decision. European candidate Tina McKenzie speaks of her support for party leader Basil McCrea "at this time".
- Polling stations across the province open for voting in European and local council elections.
- News emerges that Mr McCrea faces allegations of inappropriate sexual activity after he sent an email to party colleagues denying the claims.
- Shortly after polls close Ms McKenzie announces her resignation from the party executive with immediate effect, saying that "fresh politics" had been let down by "old politicians".
- Mr McCallister appears on BBC saying that a rift was sparked because he instigated an external probe into rumours over Mr McCrea.
- Mr McCrea tells BBC Radio's Good Morning Ulster that he has done nothing wrong and says the allegations were only brought to his attention on Thursday.
- Ms McKenzie attends Belfast City Hall and confirms she is "absolutely devastated" at the turn of events.