Should a Christian hotel-owner be allowed to refuse a gay couple a double-bed, or is such discrimination no more than bigotry which the law should not allow them to indulge?

The case of Christian hotel-owners Peter and Hazelmary Bull is currently before the Court of Appeal. Earlier this year, the Evangelical couple were ordered to pay compensation to a couple in a civil partnership who had been turned away from their establishment in Cornwall. The conflict is easier to describe than to solve: the law regards civil partnership as equal, in almost all respects, to marriage. But the God worshipped by the Bulls does not.

There would be less debate if the Bulls had refused to employ a receptionist because they discovered that she was in a lesbian relationship, or indeed if they had refused to allow a lone gay man to occupy a single room. But the intimate circumstances of bed-sharing do seem to complicate the situation. The Bulls claim that only married couples are allowed to sleep together in their beds, and that any other arrangement would be an indulgence of sin. Put bluntly, the matter at issue isn't sexual orientation, it's sex - or rather the possibility of sex.

There's some dispute about whether, in fact, the Bulls have been quite so strict about unmarried heterosexual couples as they claim. A prominent member of the National Secular Society who stayed at the hotel in 2006 with his female partner reports having had no trouble getting a room (though they were a bit disconcerted to discover "religious tracts all over the place" once they had booked in). Be that as it may, if the bed being offered is a double one, then the owners are in effect facilitating sexual conduct that may go against their deeply-held convictions.

It's no coincidence that religion has emerged in recent years as a major battleground of social and legal rights. There have been rows about Islamic dress, crosses in the workplace, nurses praying for their patients, sex education in schools. In human rights law spiritual belief occupies an ambiguous status. It is both a category of protection -- for religion is increasingly seen as a source of personal identity -- and a cause of discrimination. It's not always easy to distinguish between the two. Behaviour which a believer may regard as intrinsic to his or her religious identity may involve inconveniencing or discriminating against other people, who also have rights. The law, and society, must choose whose right to upheld. Someone must lose.

Can philosophy help? The British Humanist Association has recently put out a pamphlet, Right to Object?, which takes a broader view of some of the issues at stake.

In his introduction, Alan Howarth locates the point at issue in the conflict between two principles: that of obeying the law (necessary for a functioning society) and that of following one's own conscience, without which one can scarcely be said to enjoy moral autonomy. Balancing the two involves defining a sphere of exemption from what would otherwise be legal requirements. Such a definition, Howarth writes, "must appear especially desirable in a society which prides itself upon its liberalism, tolerance, and its respect for the moral autonomy of individuals." This is true enough, but it does suggest that a certain self-congratulation may be at work here, and also perhaps an element of wishful thinking.

As the philosopher Peter Cave points out in his essay, the weighing and balancing that judges engage in when deciding difficult cases "are smokescreens for 'muddling through'". His own view, which I tend to endorse, is that the law should err on the side of liberality, allowing "a thousand preferences to bloom" provided that there are not significant social ill-effects. He would allow the right of a small hotel run by Evangelical Christians to refuse to offer a gay couple a double-bed, but also allow companies to enforce dress-codes that make no allowances for religious dress. What this seems to mean in practice, though - and what may be going on at a deeper level - is the privileging of the interest of both employers and service-providers at the expense of both employees and customers. Is this really sustainable?

In the case of Mr and Mrs Bull, their preference for a hotel run on the basis of traditional Christian morality need not unduly inconvenience gay couples provided that most hotels don't impose such restrictions. Indeed, hotels like the Bulls' might be said to increase consumer choice for Christian holidaymakers who share their unease at being in the proximity of gay sex.

And consider the converse case. There are hotels and guesthouses that specialise in serving members of the gay community, and may wish to turn away heterosexual couples. In February 2011, shortly after the Bull case came to court, the Equality and Human Rights Commission (in a typical piece of empire-building) announced that they would look into whether gay-only hotels discriminated against straight guests, even though it hadn't actually received any complaints.

In response, the owner of a gay hotel in Bournemouth complained that that Equality Act was a "double-edged sword" that was "killing gay culture." And indeed, one hotel in Blackpool that used to boast openly that it was "exclusively gay" now states on its website that it "welcomes all guests, new and old", presumably in response to the EHRC move. This is surely a perverse outcome of laws designed to protect minorities from discrimination. In the name of diversity, a bland conformism prevails, reducing choice and opportunity for customers as well as owners.

I strongly support the right of bar and hotel-owners to run single-sex gay-only establishments, so long as they are clearly signposted as such. They provide an important service to their community which would be compromised if they were forced to open their doors to heterosexuals. The quid pro quo must be the right of a few Christian hotel-owners to run their enterprises upon openly religious lines.