Whilst the book focuses on why Christianity has declined in influence in the USA, it seems to hold some correlations for the UK. Tim Keller summarises Douthat's 5 main social catalysts (since the 1960s) for decline as:
1) First, the political polarization that has occurred between the Left and Right drew many churches into it (mainline Protestants toward the Left, evangelicals toward the Right). This has greatly weakened the church’s credibility in the broader culture, with many viewing churches as mere appendages and pawns of political parties.
2) Second, the sexual revolution means that the Biblical sex ethic now looks unreasonable and perverse to millions of people, making Christianity appear implausible, unhealthy, and regressive.
3) Third, the era of decolonization and Third World empowerment, together with the dawn of globalization, has given the impression that Christianity was imperialistically “western” and supportive of European civilization’s record of racism, colonialism, and anti-Semitism.
4) The fourth factor has been the enormous growth in the kind of material prosperity and consumerism that always works against faith and undermines Christian community.
5) The fifth factor is—that all the other four factors had their greatest initial impact on the more educated and affluent classes, the gatekeepers of the main culture-shaping institutions such as the media, the academy, the arts, the main foundations, and much of the government and business world.