The Roman Catholic Church's top official on evangelisation issues, Cardinal Ivan Dias, told Anglicans meeting at the Lambeth Conference this week that the two Churches must work harder on the issues that unite them if both their mission efforts are to be effective.

"The more Anglicans and Catholics are able to study issues together and to discern an appropriate Gospel response, the stronger will be the impact of their mission endeavours," Cardinal Dias, Prefect of the Congregation for the Evangelisation of Peoples, said in an address on Tuesday night.

Efforts towards greater unity between the Anglican and Catholic Churches have been jeopardised by the ordination of homosexual clergy and women bishops in the Anglican Communion.

Cardinal Dias warned that evangelisation would be hampered without unity and cohesion between churches and their leaders, as well as between denominational leaders.

"When they are of one mind and heart notwithstanding their diversity, their missionary thrust is indeed enhanced and strengthened. But, when the diversity degenerates into division, it becomes a counter-witness which seriously compromises their image and endeavours to spread the Good News of Jesus Christ," he told the bishops, who are gathered at the University of Kent in Canterbury for the once-in-a-decade conference.

The Cardinal also warned the bishops not to abandon tradition or the guidance of leaders.

"When we live myopically in the fleeting present, oblivious of our past heritage and apostolic traditions, we could well be suffering from spiritual Alzheimer's. And when we behave in a disorderly manner, going whimsically our own way without any co-ordination with the head or the other members of our community, it could be ecclesial Parkinson's," he said.

The Cardinal urged Anglicans not to compromise on the uniqueness of Christ as Saviour in face of such challenges as secularism, spiritual indifference, relativism and the "culture of death" seen in abortion and divorce.

A number of 'ecumenical partners' were specially invited to attend Lambeth by the Archbishop of Canterbury, including Cardinal Dias, emerging church leader and evangelist Brian Mclaren, and head of the World Evangelical Alliance, Dr Geoff Tunnicliffe.