London's mayor has formally opened an investigation into historic claims of inappropriate behaviour and financial misconduct by his deputy.
Ray Lewis, who has responsibility for youth, faces multiple allegations relating to his time as a priest and as founder at an academy for young people.
Mr Lewis described the allegations as rubbish and groundless.
Mayor Boris Johnson said the former chief of the Prison and Probation Service would head the investigation.
Mr Johnson announced Martin Narey would lead the inquiry, which is due to start on Tuesday and is expected to take a month.
He said he had "every confidence in Ray Lewis".
The Mayor of London's office confirmed the accusations related to alleged inappropriate behaviour with a parishioner in the late 1990s and while at the Eastside Young Leaders Academy - a youth scheme founded by Mr Lewis in east London in 2003.
I have never defrauded anyone
Separate claims of financial irregularity centre on money entrusted to the deputy mayor while he was a vicar.
BBC London's Political Editor Tim Donovan said police investigated complaints about financial irregularities in the late 1990s but no criminal action was pursued.
In one case, the allegation centred on a sum of more than £25,000 entrusted to Mr Lewis by a female congregant in the Parish of St Matthew, West Ham, in the Diocese of Chelmsford.
The Right Reverend John Gladwin, Bishop of Chelmsford said he was placed under formal Church of England disciplinary structures between 1999 and 2005 and had his ministry restricted.
London deputy Mayor speaks to deny misconduct allegation
"This was because a misdemeanour of such seriousness had been committed that in the opinion of the Archbishop, the person concerned should not exercise his ministry for the time being," he said.
At a press conference at City Hall on Thursday, Mr Lewis claimed he was not aware he had been struck-off and that he was still a vicar in the Church of England.
"I'm not a saint. I speak my mind and sometimes I rub people up the wrong way," Mr Lewis said.
"But I am not the person painted by these allegations. I have never harassed anyone. I have never defrauded anyone."
Mr Lewis left the church in 1997 to take up a post abroad.
When he returned to England in 1999, he was unable to resume a career in the church and joined the prison service.
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