When Bishop Michael Nazir-Ali was born in Pakistan to Christian converts from Islam, his rise to being a distinguished bishop and senior figure in the Church of England could hardly have been anticipated.

He is also one of the most outspoken Church of England leaders, especially since he left the role of diocesan bishop and joined the Oxford Centre for Training, Research, Advocacy and Dialogue.

Nazir-Ali's new book, "Triple jeopardy for the West", is a collection of his writings and broadcasts over the last three years with some new material, gathered together to form a contribution to the debate on the direction of British culture. His assertion is that there are three current and serious threats to the Christian culture of British life: secularism, Islamism and multiculturalism.

Aggressive secularism, he says, is the force within society to remove Christianity from the public arena. This goes further, he asserts, than a moderate secularism that allows a generous toleration of all religious viewpoints, but is a force of totalitarian ideals that leaves no space for freedom of belief. His concern is not just for the effect this kind of secularism has on the church, but the way it leaves people without any moral bearings to live by.

Nair-Ali is strongest on his consideration of aggressive Islamism. He sees radical Islam with an agenda of religious imperialism as a genuine threat to the Christian culture of Britain. British Islam, he says, has changed in the last generation, from a quiet religion of mysticism to a radical, political movement led by clerics who are allied to fundamentalist movements.

The third "threat", multiculturalism is more difficult to pin down. The author sees this as a "new-fangled and insecurely-founded doctrine" which encourages different cultural norms to prosper side-by-side with no room for them to engage with one another or seek integration. It has also led to the exclusion of faith from public life.

As a "state of the nation" report this book is of great value. In it we hear one of the best-informed minds in our country express his concerns about the country we live in. Perhaps the weakness of the book, though, is that it tries to do too much. As much of the material has appeared in other places and in other forms over several years, the treatment here seems rather bitty and piecemeal, with some chapters off topic and misplaced.

The other concern is that he is not critical enough of the church in Britain. British Christianity, and not least the Church of England, has to take its share of the blame for creating a society of imperialist intent and one that has a lack of definition of its core beliefs. A book like this needs to be as much a call to the reformation of the church as to the wider world.

What Nazir-Ali does do well is to urge Christians to get involved in public life, and for any who will hear his call this book is well worth reading, considering, and arguing with at times, and then putting into action to see the nation changed not by angry words but by sacrificial service.