The Church of England is guilty of "corporate failure" because it has not properly spread the message of Christ, the Archbishop of York has said.
Dr Sentamu said British society was becoming selfish and cynical
Dr John Sentamu said the Church had instead become engaged in "endless debates" about issues like the ordination of homosexual priests.
"The Church has not been very good at clearly spelling out what the message of Jesus is about," he told the BBC.
That had allowed "illiberal secularism" to produce a "very cynical" culture.
In an interview on BBC Radio 4's Today programme, Dr Sentamu denied his comments were intended as a criticism of the leadership of the Archbishop of Canterbury, Dr Rowan Williams.
However, he acknowledged that one of his concerns was the debate over whether to ordain homosexual priests and bishops which is threatening to split the worldwide Anglican Communion.
"It is a corporate failure of the Church, not actually doing the ministry of Jesus Christ out in the world," he said.
"All of us as members of the body of Christ need to do more.
"What we should be about is telling people that God in Jesus has come in a human form, died, rose again and his presence, in terms of the spirit, actually transforms lives."
Dr Sentamu described the fall in average attendances at church services as "worrying", and warned that the decline of traditional faith was having a damaging effect on society.
"The trouble you have got is that there is a desire for self-fulfilment," he said.
"Unfortunately, as we see it in this country, it turns out to turn into self-assertiveness and very little self-examination and we end up with a culture which is very cynical, blaming somebody else, constantly endeavouring to put other people down."