A "me" culture that has replaced a "we" culture in western society, an American preacher who is a spiritual adviser to President Barack Obama told the General Synod.

Rev Jim Wallis, a leading light on the evangelical Christian left in the US and the founder of the popular Sojourners movement, warned nearly 500 clergy, bishops and laity not to succumb to cynicism.

"Scepticism is fine but cynicism is a buffer against personal commitment," he said.