Two Christians are to appeal for the right to turn couples away from inns. It is reported that in making this appeal they are being supported by the Christian Institute.

On one level this is all quite bizarre. One would perhaps expect Christians to be rather less judgemental, in accordance with the recorded liberal and inclusive teachings of Jesus of Nazareth. After all, he was welcoming to sex workers and even tax collectors. But, then again, how the many Christians who believe Mary being impregnated by a "god" is somehow more normal than gay sex has always been quite beyond me.

However, the contentions of the hoteliers in this case are troubling regardless of any seeming conflict between homosexuality and a distorted form of Christianity. Indeed, there is a very basic legal principle at stake.

It is a great and ancient English legal tradition that any hotel is in principle open to any guest. Inns, like toll bridges and ferries, should be open to all comers who are able to pay their way.

As a legal tradition, this predates the Victorian legal invention of extreme freedom of contract doctrine. It was simply not open to the innkeeper, the tollhouse, or the ferryman to refuse to enter into a contract on a whim. There was always a greater public interest than selfish contractual autonomy.

This area of law, aspects of which are called "common carriage", is still highly relevant today. Modern telecommunications and utilities law is to a large extent premised on such rules of "common carriage". It also informs the ongoing debates on net neutrality.

The duties that one owes to strangers are central to any developed system of law, as they are to any sensible system of ethics. In both legal and ethical contexts, there is long tradition of valuing the hospitality to be given to travellers and guests.

So it is saddening that some followers of the very religion that gave us the parable of the Good Samaritan appear now to be completely unaware of this.

David Allen Green is legal correspondent of the New Statesman.