Secularization is a subject about which it seems it is almost impossible for authors to be dispassionate. While historians are often more likely to adopt the term, within sociology the debate over its use has become somewhat heated, and there are seemingly more authors to be found who deny its cogency than can be found to defend it. In the context of British religion, this often appears to be the product of hope over experience. Nevertheless, since Casanova's Public Religion in the Modern World, sociologists have taken a global perspective on secularization, noting the ongoing strength of both Islam and Christianity outside of Europe. This led Peter Berger, once a doyen of the secularization theorists, to criticize the term's Eurocentrism, and identify the trends contributing to the ‘desecularization of the world’. The edited collection reviewed here extends the logic of these trends to London, now widely considered a ‘global city’.

The focus of the collection is on Christian denominations. The key claim advanced by the editors is that the 50 per cent increase in congregations in the capital since 1979, alongside a 10 per cent increase in Sunday Worshippers, represents a ‘desecularization’ of the city. On the one hand, as the volume as a whole shows, over the past 40 years London has seen significant changes in form of religious practice adopted in the metropolis driven largely by in-migration from a great range of countries, many of which are evidenced here. Whether or not this represents desecularization is, however, a matter of perspective, and when London's population growth over the period is factored in the growth of Christian denominations begins to look somewhat more marginal than the authors appear to want to admit. Thus, while on their own figures, the number of Christian congregations grew from 3,400 in 1979 to 4,791 in 2012, the population of Greater London also grew by about 2 million. This does represent a per capita expansion of Christian places of worship, but at an increase of around 7 per 100,000, it is a small (albeit significant) one, and, as the authors also note, the number of census Christians in the city continues to decline. At the same time, of the other major faiths represented in London, all but the Jewish population has increased in number in the period covered by the book. We might therefore be inclined to question not only the volume's major claim, but also its focus.

Notwithstanding the foregoing, the collection does offer a valuable insight into the changes taking place in Christian communities in London over the past 40 years. The chapters by Kaufmann and Brierley present ample statistical evidence to describe these changes, in which the dramatic rise of Pentecostalism is key to the story. On Brierley's figures, this form of Christianity is now the largest grouping by attendance. An insight into this ‘Pentecostalization’ of the city is offered across several of the chapters, including that by Andrew Rodgers, which takes a walk down the Old Kent Road to discuss the growth of new Black Majority Churches in a manner which is likely to appeal to urban historians. Also dealing with Pentecostalism is the chapter by Babatunde Adedibu, which chronicles the Redeemed Christian Church of God's mission to London. Founded by Nigerians, this church has turned the centuries-old flow of missionaries back to the metropole. Adedibu's chapter ranks among several insider accounts included in this volume, which also includes the work of Anglicans, Baptists and a Methodist. All of these provide valuable insight, and Bob Jackson's chapter, and Alan Piggot's chapter on the Church of England and Methodism respectively are able to draw on extensive statistical evidence collected by these denominations. Beyond this, Colin Marchant's chapter provides extensive evidence for the impact of demographic change on religious practice in Newham. This contains a lot to unpack and might offer a starting point for future research on this subject.

Despite the deficiency of the overarching claim, then, the book contains much insight into the changing shape of Christianity in the capital, with much in the form of accounts of the religion of immigrant populations, which besides the activities of Nigerians also covers Brazilians, Russians and the various visitors to Westminster Cathedral. The ‘big hitters’ included in the collection are Grace Davie and John Wolffe and their work will be well known to anyone with an interest in the sociology of religion and religious history respectively. Wolffe contributes a longer-term perspective, arguing that statistical evidence suggests that practising Christians in London are currently at levels last seen in the Edwardian period. He continues by narrating the declining fortunes of ‘traditional’ denominations, and the recent rise of others across the twentieth century. Davie, who has been a key player in the widening out of the secularization debate beyond a discussion of institutional religion, also contributed a chapter to Berger's (1999) Desecularization collection, raising questions about what factors have made European secularity an exceptional case. Here, she revisits these themes and provides an up-to-date survey of different influences on contemporary religious practice in the UK. Although she herself ends on an equivocal note over whether London is the site of desecularization, she is able to show the ways in which London has now departed from European trends and offers a tour of the religious constitution of London's boroughs.

Urban and social history of religion of the late twentieth century and early twenty-first century is understandably somewhat sparse at present. Nevertheless, at some point, historians will have to come to grips with the effects of in-migration on religious belief and practice and despite my misgivings over its central claim and focus, this book will provide a good starting point.