Most Roman Catholic priests in England and Wales do not support the Church's ban on artificial contraception, according to the largest survey of their opinions.
The poll of 1,482 priests - almost half their total number - found that 43 per cent actively opposed the Vatican's stance on contraception, while a further 19 per cent were unsure whether to support the Church's official policy.
The poll also found that one in four priests was no longer convinced of the need for chastity, while 21 per cent argued that practising homosexuals should be allowed in the priesthood.
Even more startling, given the Catholic Church's recent embroilment with child abuse scandals, was the fact that one in 10 questioned felt that paedophilia should not rule out priests from active ministry.
The seven-year survey was conducted by Mgr Stephen Louden, a Roman Catholic priest and former Roman Catholic chaplain to the Armed Forces, and Leslie Francis, a professor of pastoral theology at the University of Wales.
Questionnaires were originally sent out in 1996 to all 3,581 secular and regular Catholic priests serving in parochial appointments in England and Wales.
Almost half the priests responded, making it the largest survey of its kind. The most recent comparable study was undertaken in 1977, surveying 412 Anglican clergy, Methodist ministers and Catholic priests in England and Wales.
Prof Francis told The Telegraph: "This contains potentially explosive information for the Catholic Church. It is a very, very interesting document." The results, which will be published in September by Continuum Books under the title The Naked Parish Priest, also reveal an increasingly liberal trend among younger priests.
While four out of every five priests aged 60 or over took the view that a practising homosexual should be barred from the ministry, that figure fell to three out of every five among the 45-59 age group, and almost one in two (47 per cent) among those under the age of 45.
The report concludes: "The greater acceptance of homosexuality among the youngest cohort of priests may simply indicate a greater willingness to accept alternative sexualities, or it may indicate a higher predisposition towards homosexuality among the younger priests themselves."
In a Church where there is an official embargo on even debating the possibility of ordaining women, 25 per cent of those surveyed said that they believed that a woman could be ordained a bishop. A growing number of Catholic priests also argued for increasingly liberal attitudes on issues such as adultery and divorce: 40 per cent believed that the Church's attitude to divorce and remarriage should be liberalised. More than half (61 per cent) do not believe that sex with a married woman should debar priests from practising.
Many of the opinions directly contradict the teachings of the Catholic Church. The use of artificial contraception was outlawed by Pope Paul VI in his 1968 encyclical, Humanae Vitae, and the Church has consistently condemned all homosexual activity as sinful.
Pope John Paul II also stated in an Apostolic Letter in May 1994 that the Church was not authorised to ordain women and that such a belief was a fundamental tenet of the Catholic faith.
Fr John Skivington, a 70-year-old parish priest at St Paul's Roman Catholic Church in Cramlington, Northumberland, said that the Vatican should take careful heed of the survey's findings. "I am very surprised that one in 10 feels that paedophilia should not bar a priest from practising: I would say that it definitely should. However, I am reasonably heartened that 25 per cent feel that a woman could be validly ordained bishop and I would count myself among their number.
"I do feel that the Church authorities occasionally pay scant attention to the changing feelings of the laity. Rome states their views and everyone has to toe the line. I think that's barmy. If we fossilise, then we die."
A spokesman for the Catholic Bishops' Conference of England and Wales questioned the methodology of the survey, saying that the questions were "very general and, on occasions, confused and confusing to the respondents".
He added: "It is a work of an Anglican clergyman and academic and his former doctorate student, a Catholic priest. As such, it was unofficial and was not welcomed by most of the priesthood.
"For all these good reasons, the statistical findings of this book must be treated with great caution and cannot be seen as a true reflection of the current beliefs of priests in England and Wales."
Fr Shaun Middleton, a spokesman for the National Conference of Priests, said: "I have some serious questions about the methodology and sample base that was used for this work. A number of areas highlighted give priests cause for reflection.
"However, I do not think the views contained in The Naked Parish Priest can be taken as normative. In my opinion, they do not reflect the views held by the majority of priests working in England and Wales."