In their judgment in the Johns fostering case a couple of weeks ago, Justices Munby and Beatson declared that, although England has an established church, ‘the laws and usages of the realm do not include Christianity, in whatever form’.

Whether or not the case ought ever to have been brought in the first place – the Evangelical Alliance questions this – the judgment is troubling at several levels. Whatever one’s views of the appropriate criteria for fostering or whether the Johns met them, the case is a good deal more complex than some commentators have recognised. Although the judgment brings up a number of contentious points, perhaps the biggest question it raises is whether there is any longer a meaningful sense in which we can speak of Britain as ‘Christian’.

There are (at least) four senses of the term ‘Christian Britain’. The first is sociological. A nation could be termed ‘Christian’ if a significant majority of its population adheres to Christianity. If we take regular church attendance as an indicative benchmark, it’s clear that only a minority – no more than 10% – of people resident in Britain is Christian. The figure is disputed and the forthcoming census is unlikely to resolve the argument, however people choose to respond to the British Humanist Association’s appeal to the non-religious to come clean and state their true convictions. Justices Munby and Beatson are right to claim that Britain is clearly no longer Christian in this sociological sense, but rather ‘a multi-cultural community of many faiths’.

The second is constitutional. There are two ways in which any state could qualify as constitutionally Christian: if its constitution explicitly endorses the Christian religion, as in art. 44 of the 1937 Irish constitution, or if there is an established church, as in England since (at least) 1534. England clearly is ‘Christian’ in this latter sense. ‘Britain’ is a more complex matter, yet in the words of the House of Lords Select Committee on Religious Offences in England and Wales: ‘the constitution of the United Kingdom is rooted in faith – specifically the Christian faith exemplified by the established status of the Church of England… The United Kingdom is not a secular state’. In light of this, it is puzzling that the judges in the Johns case should declare that the laws of England ‘do not include Christianity in whatever form’. Yet as an Anglican who has long favoured the progressive dismantling of the apparatus of establishment, this isn’t a sense of Christian Britain I would man the ramparts for.

The third sense is historical. Prominent Christians are increasingly arguing that some of our fundamental political values – the rule of law, human rights, tolerance, democracy or hospitality to foreigners, for instance – were bequeathed in part by the historical legacy of Christianity (even if they were often resisted by some Christians) and that they will become threadbare if that legacy is repudiated by public institutions. (Click here for a forthcoming Theos publication on the subject). This view is not limited to Christians; a version has been endorsed by the leading secularist philosopher Jürgen Habermas. I agree that something like it could be vindicated, but doing so would require a good deal of careful and inevitably contested historical argumentation. And even assuming such claims could be substantiated, it is not clear to me how they could resolve any contemporary political disagreements, vulnerable as they are to the flat response of Justices Munby and Beatson: ‘that was then’.

There is, however, a fourth sense, which we might simply term ‘democratic’. Suppose the great majority of the Christian minority in Britain acted publicly in ways consistent with the ethical implications of their Christian faith – in business, education, the environment, welfare, family life, or foreign relations. Suppose they disavowed legal privilege and acknowledged their minority status alongside others in a plural democracy. Suppose they also allowed their principles consciously to shape their democratic activities as citizens, activists or office-holders, in ways appropriate to the specific remit of government. Suppose the cumulative influence of such Christian political engagement began over time to shape law, public policy, even judicial reasoning – challenging immoral arms trading, financial greed, unsustainable consumption, convenience abortion, and easy divorce.

Gordon Brown seemed to be entertaining something like this in a thoughtful speech hosted by the Archbishop of Canterbury last month. Urging a rejection of both ‘theocracy’ and ‘liberal secularism’, he called for ‘a strong faith politics which is part of an open and teeming public square, part of a deliberative politics that allows each citizen to bring the richest account of themselves to the public square’. The result would be a Britain in which effective and informed Christian democratic influence was brought to bear modestly, constructively and yet confidently – perhaps sometimes even decisively – on pressing issues of public justice. That’s a ‘Christian Britain’ worth fighting for.

Jonathan Chaplin is Director of the Kirby Laing Institute for Christian Ethics and co-editor, with Nick Spencer, of God and Government.