ONE element of received opinion has been that, while church attendance in Britain has been flaky, in the United States it remains solid. But, even in the US, numbers, appearances, and interpretations are in a state of flux.

The rise of those describing themselves as "unaffiliated" has increased from just over 15 per cent to just under 20 per cent of US adults in the past five years, the independent Pew Research Center reports (www.pewforum.org/topics/religious-affiliation). This and other developments suggest that the two sides of the Atlantic could be converging in patterns of Christian faith.

I was at a Christian liberal-arts college in Michigan recently, where the auditorium was full with more than 1000 people for midday prayers on a Friday. The last time I had been to worship like this in the US was in the early 1980s, and it was as if nothing had changed.

This act of worship was also part of the 2013 Festival of Faith and Music at Calvin College (think smaller-scale Greenbelt, on a campus). Some of the contributors suggested a chill wind blowing across the Christian heartlands of the US. The rise in younger people leaving churches and designating themselves as having "no religion" ("nones" as they are known) is causing serious re-evaluation (Comment, 21 June).

A similar note was struck the following Sunday at Mars Hill megachurch, founded by the Revd Rob Bell (Features, 12 April). A relatively youthful pastor reflected on his experiences with high-school students and their lack of interest in baptism. He acknowledged ruefully that this generation was indifferent to any form of institutional affiliation.

From an Anglican perspective, Diana Butler Bass, an academic and retreat-leader, has argued that a metamorphosis of religion is taking place in the United States. In Christianity After Religion (Harper One, 2012), she draws on a 2008 survey from the Pew Research Center.

This concludes: "More than one quarter of American adults (28%) have left the faith in which they were raised, in favor of another religion - or no religion at all. . . The survey finds that the number of people who say they are unaffiliated with any particular faith today (16.1%) is more than double the number who say they were not affiliated with any particular religion as children."

Dr Bass argues that the Christian awakening that many predicated under the "Religious Right" in the 1980s has developed into something different. Then, forces of Christian conservatism sought to reverse the social changes of the 1960s, and to escape from the world. But this process has run into a blind alley.

Instead, she believes, a new "Great Awakening" is now under way in all manifestations of faith across the US, but in an alternative direction to that envisaged by the Religious Right. This change is rooted in the common distinction between religion and spirituality ("I'm spiritual but not religious"), and is being driven by three questions that are currently reshaping religion: What do I believe? How should I act? Who am I?

This view seems to be confirmed by further research from the Pew Center in 2012 on the rise of "nones". The most recent report observes that: "Their ranks now include more than 13 million self-described atheists and agnostics (nearly 6% of the US public), as well as nearly 33 million people who say they have no particular religious affiliation (14%)."

In analysing those who are unaffiliated, the report argues that many "are religious or spiritual in some way. Two-thirds of them say they believe in God (68%). More than half say they often feel a deep connection with nature and the earth (58%), while more than a third classify themselves as 'spiritual' but not 'religious' (37%)."

ONE response to the changing religious landscape of the United States is being mapped out by James K. A. Smith, a philosopher from Calvin College, in his three-volume Cultural Liturgies project. In the second part, Imagining the Kingdom (Baker Academic, 2013), he argues that Christian living is no longer driven by doctrine or intellectual beliefs, as he believes it was in much of the post-Reformation and Enlightenment period, but by character, practice, and ritual.

Key to this are: (i) the primacy of love and of the imagination in shaping our identity and orientation to the world; (ii) embodied communal rituals (liturgies), including secular liturgies; (iii) resituating Christian worship in its relationship to the world. Professor Smith contends that we are formed in the embodied stories that we tell both inside and outside the Church.

So the Church cannot take refuge in itself: it must engage wholeheartedly with the world. In this context, for Professor Smith, the truth of Christianity is that of story, metaphor, and poetry. Socially and theologically, he is standing on similar ground to that identified by the Revd Professor David Brown in the UK, in his work on theology, culture, and the arts.

Hugh Laurie (the British actor known from the US medical drama House and his earlier comedy partnership with Stephen Fry) argued recently in a Perspectives documentary on ITV that, for the most part, the difference between the UK and US was one of degree - five per cent was the figure he gave. The exception to this, he believes, is faith, because, "When it comes to religion, then it's 3000 per cent."

There may be an element of truth in this hyperbole for the moment. But the situation is changing rapidly, and the percentages between the two nations are much closer when we look at the generations emerging into and from higher education.

Those who see themselves as "spiritual but not religious" are increasing on both sides of the Atlantic. The common ground identified by Professor Smith and Professor Brown provides a vital means of engaging in conversation with this emerging constituency.

The Revd Dr Vaughan S. Roberts is Team Rector of Warwick, and the co-author with Clive Marsh of Personal Jesus: How popular music shapes our lives (Baker Academic, 2012). His writings are at http://works.bepress.com/vaughan_roberts/.