The Archbishop of Canterbury has admitted he is powerless to stop an ex-vicar jailed for child sex offences from using the title "Reverend".
Guy Bennett, who was a vicar in Oxted, Surrey, was sentenced in 1999 for indecently assaulting three girls.
Bennett was photographed in 2008 wearing a clerical collar.
Writing to another of Bennett's alleged victims, Justin Welby said Bennett had been disqualified from holding any office in the Church.
Lucy Duckworth, who made a complaint of sexual abuse against Bennett to Surrey Police in 2008, had written to the archbishop about Bennett.
The former vicar, who retired when under suspension pending the outcome of his trial, denies assaulting Ms Duckworth or referring to himself as "the Reverend".
The Most Reverend Justin Welby wrote in reply to Ms Duckworth: "Regrettably, although we can ban someone from ever officiating at worship and wearing robes for worship, or passing themselves off as a priest in good standing, we cannot prevent them from using the the title 'the reverend' or even wearing a clerical collar."
He continued: "In fact anyone is able to wear such dress, providing they do not do so for illegal purposes.
"It is not contravening any law unlike say dressing as a police officer."
Bennett, who was vicar of St Mary's parish church in Oxted, admitted indecently assaulting the girls between 1976 and 1988 and was jailed for nine months and put on the sex offenders register for 10 years. At his trial he denied four further offences which were left on file.
The Church of England suspended him when the police inquiry began.
'Bemused, baffled, angry'
Ms Duckworth alleges she was sexually abused by Bennett when she was at school. He was never prosecuted for the alleged abuse.
After raising the issue with the archbishop and receiving his reply, Ms Duckworth said: "It leaves me feeling bemused, baffled, angry, frustrated and absolutely shocked that this is happening.
"If he's powerless to remove convicted child abusers from the institution then they've got some real questions to be asking themselves."
Analysis: Colin Campbell, BBC South East special correspondent
By sending his letter and expressing his desire to be able to restrict convicted priests from calling themselves Reverend, the Archbishop of Canterbury Justin Welby has opened up a very important safeguarding debate within the Anglican Church.
In 2013 an inquiry ordered by the former Archbishop of Canterbury Rowan Williams into the Diocese of Chichester called for "urgent consideration" to be given to the same issue, saying those "who are suspended or prohibited should not be permitted to wear any clerical dress on any occasion".
To date that has not materialised. The Church is, however, contemplating making it an offence for clergy to robe in churches if they have been banned. It remains acceptable for banned and convicted clergy to continue calling themselves Reverend.
The Church of England's new mantra is "survivors come first". But those who say they've been harmed believe the Church is continuing to give shelter to clergy who've abused.
Speaking to the BBC, Bennett denied abusing Ms Duckworth.
Bennett said he does not refer to himself as "Reverend", but others do and he does not stop them.
He also said he had not worn his clerical collar for more than 10 years.
Surrey Police said the force received a complaint in October 2008 about allegations of sexual offences and, after carrying out investigations, passed the case to the Crown Prosecution Service (CPS).
The CPS said: "It was decided that there was not enough evidence to provide a realistic prospect of conviction in this case. "