A passionate plea to understand those who don't see God in quite the way others do was made at a packed Christian unity service in Winchester.

"When are we ever going to tackle this idea that, somehow, the people who don't know God by our name don't have real access to him?" asked the Rt Revd Jim Thompson, the former Bishop of Bath and Wells and BBC Thought for the Day broadcaster.

"We don't see God clearly by diminishing other people."

He gave the address in St Peter's Catholic Church on Sunday evening. Speaking as preparations proceeded for a possible war with Iraq and when Muslims and Christians were sometimes at loggerheads, he said: "We live in a rapidly changing world, a dangerous world. There is access to God, in Christ, through prayer, the sacraments and scriptures. But it remains 'through a glass darkly'. We don't know everything. I believe the world needs humility before the mystery of God."

He said the Chief Rabbi, Jonathan Sacks, was having to rewrite his book, The Dignity of Difference, about how to avoid the clash of civilisations, because some clerics in Jerusalem objected to parts of it.

"The clash of civilisations will destroy us unless we understand the other person's values and how to react to them," he said.

"We need to express ourselves in a way that shows we are one of the whole human family."

The parish priest of St Peter's, Monsignor Peter Doyle, who is 12 years in post this week, welcomed the congregation, which was so large that 70 to 80 people had to stand.

The Revd Stephen Marr, who chairs Churches Together in Winchester, gave the final blessing.