In September, when Bishop Fellay was handed the preamble, the Vatican did not publish the document but said it "states some doctrinal principles and criteria for the interpretation of Catholic doctrine necessary to guarantee fidelity" to the formal teaching of the church.

In his interview, however, Bishop Fellay said the preamble was "a document which can be clarified and modified, as the accompanying note points out. It is not a definitive text."

"The proposal that I will make in the next few days to the Roman authorities and their response in turn will enable us to evaluate our remaining options. And whatever the result of these talks may be, the final document that will have been accepted or rejected will be made public," he said.

Asked whether the past two years of talks with the Vatican have been pointless, Bishop Fellay said they have allowed the society to present their objections to the doctrinal difficulties caused by Vatican II "and consequently show why adherence to the council is problematic. This is an essential first step."

"In Rome itself, the evolving interpretations given to religious liberty, the modifications that have been made on this subject in the Catechism of the Catholic Church and in the Compendium of it, the corrections that are currently being studied for the Code of Canon Law ... all this shows the difficulties that you run into when you try to abide by the conciliar documents at all costs," Bishop Fellay said.

"From our perspective, this nicely shows the impossibility of adhering in a stable way to a doctrine in motion," he added.

The eventual "canonical solution" envisioned by the Vatican for the society was expected to take the form of a personal prelature, or a church jurisdiction without geographical boundaries. Bishop Fellay said such an arrangement would be pointless unless the doctrinal differences were resolved.