MERCY has not been the Roman Catholic Church's "strong suit" in the past 30 years, the Archbishop of Westminster, Cardinal Vincent Nichols, said last week. But permitting those who had married after divorce to take communion could not happen without "quite a radical rethink" of teaching, he said.

Speaking in advance of the two-week extraordinary synod on the family which is due to begin in Rome on Sunday, Cardinal Nichols sought to dampen hopes of a dramatic outcome. He compared it to "the first movement of a piece of music", to be followed by the ordinary synod next year, and the "finale" of "whatever the Holy Father concludes".

The extraordinary synod on "the pastoral challenges of the family in the context of evangelisation", convoked by Pope Francis a year ago, is the first synod on the family since 1980. After the announcement, a questionnaire was issued to Roman Catholics around the world, to elicit their views on issues including contraception, marriage, and celibacy (Comment, 22 November). The results were compiled in a long instrumentum laboris (working letter) released by the Vatican in June.

This was conservative in tone, calling for mercy, but also reiterating the Church's existing teaching. On the question of communion for those married after divorce, it read: "With patience and understanding, she [the Church] must explain to these people that their not being able to celebrate the sacraments does not mean that they are excluded from the Christian life and a relationship with God."

On Tuesday of last week, Cardinal Nichols argued that any marriage that was "truly the place of the conscious, willing acceptance of God's grace can no more be dissolved than the eucharist can be returned to bread, because it is the work of God".

But he acknowledged that mercy had not been the Church's "strong suit" in the past 30 years. It would be, however, "a mistake to say that somehow the gift of God's mercy removes the need for acts of forgiveness and conversion". There was a need to "grasp again, refresh, deepen, what the Church's understanding of marriage as a sacrament really is".

In February, Cardinal Walter Kasper introduced a proposal, at a meeting of cardinals, to allow some divorced RCs who had entered into civil marriage to receive communion without having obtained an annulment or abstaining from sexual relations with their new partner. This has been firmly opposed by several other cardinals.

This month, the President of the Pontifical Council for the Family, Archbishop Vincenzo Paglia, suggested that the synod was more likely to focus on better marriage preparation and wider access to church courts for requesting annulments rather than on changing teaching.

"Problems will be addressed, but any change in doctrinal teachings would be hard, considering the diversity and complexity of these issues," he told Crux. "I do believe bishops will find real pastoral alternatives: profound human problems deserve profound solutions."