You might think it would be to discredit your opponents’ facts or undermine their logic but, in fact, the best way is simply to deny them a voice in the first place.

Although few people openly seek to silence their adversaries, when those adversaries happen to be religious (as has often been the case with the HFE bill this week), it is so much easier to deploy the “religion is private” card than actually to engage with their arguments. Hence Jackie Ashley in Monday’s Guardian: ‘There is no sensible conversation between the opposing views to be had… live according to your beliefs, but don't try to impose them on the rest of us.’

This will not do. Christian and other religious opinions should be permitted to engage in public debate, no matter how fruitless some people think that debate is. Moreover, who is the ‘us’ here? If Jackie Ashley imagines the rest of the population thinks the same way she does, she should think again.

But so should Christians. One of the major pitfalls of Christian public engagement over recent decades has been the assumption that Britain is a Christian country populated by Christian people who live by Christian values. It is not.

That is not to say that the Christian worldview no longer remains a (or even the) major influence in public life. Rather it is to acknowledge that contemporary British society is morally and culturally plural to an unprecedented degree. If Christians want to win arguments in the House of Commons or run state-funded welfare provision services, or whatever else, they need to show that they will contribute to the public good.

This is not easy. In a morally plural society like our own, the concept of the public good will differ from one person to the next. For some, it will involve unrestricted personal liberty, for others semi-restricted personal relationships, and for others highly-restricted, enforced equality.

The Christian notion of the good must be determined by Scripture and theological reflection, and not by social or political expediency. But once it is, it is up to Christians to demonstrate that the idea of the good embodied in the Gospel makes for full human flourishing.

Or, as someone once said, ‘Thus, by their fruit you will recognise them’ (Matthew 7:20).