In the end, it all came to nothing. A show of hands at the Magistrates Association's annual general meeting on Saturday was enough to see off the proposal to end the courtroom practice of witnesses swearing on the Bible. It was a defeat for secularism and a victory for the status quo. Now, in the aftermath of this strange little episode, both sides of the debate have reasons to be troubled.

Perhaps the biggest lesson to be taken is that the religious-secular divide remains acute in British public life. All Ian Abrahams, the Bristol magistrate responsible for the row, wanted to do was increase the effectiveness of the oath. His proposed replacement would have emphasised the consequences of not telling the truth by getting witnesses to state that lying means "committing an offence for which I will be punished and may be sent to prison".

"I don't intend my motion to make any comment on religion," Abrahams insisted to the Mail on Sunday earlier this month. "It is certainly not anti-religious." The newspaper did not see it that way. A former bishop spoke out, warning of the "slippery slope towards the increasing secularisation of society". Before we knew it, a full-scale row had erupted. Eventually the politicians got involved.

A group of Northern Ireland unionists led the way in tabling a Commons motion deploring the proposed change. Jim Shannon, the Democratic Unionist Party MP behind the motion, told New Humanist: "There's no need for change or this debate. It was completely unnecessary to have a debate on this thing." Without much effort he persuaded 11 MPs to sign up. "The Bible is relevant to us in every aspect of our lives," he added. "Is it relevant today? Yes it is. Was it relevant when the legal laws of the land were put together? Yes it was. It's been a guideline for a great many countries right around the world. Right and wrong is right and wrong, and the Bible indicates that to be so."

You don't have to swear on the Bible if you're giving evidence in a court, of course. The secular 'affirmation' alternative was introduced as far back as 1888, while non-Christian believers can choose to swear on other holy books like the Koran. Still, there is scepticism among some politicians that religion has any place in the criminal justice system. "I don't think the antiquated process of swearing on a holy book is helpful," Liberal Democrat MP Julian Huppert texted from the Commons chamber after his opinion was invited. "I'm not aware of evidence that this makes people more truthful - after all, those who believe 'thou shalt not lie' presumably mean it all the time."

Abrahams' public comments on the issue suggest something of a conflict. His was a pragmatic approach: in 21st century Britain, he believes, more people are likely to tell the truth when confronted with the consequence of going to prison than of going to hell. His argument was taken up by the Magistrates Association itself. It even went to the extraordinary length of writing to MPs who had signed up to Shannon's motion and arguing it was 'factually inaccurate'.

This was misleading, even if the ploy worked in the case of at least one MP. The motion would have stripped the Bible and other holy books out of the process altogether. If that isn't undermining the role of religion in public life, then what is?

Swearing on the Bible is a long way off the top of the agenda for secularist campaigners. But as the debate escalated, many found their feelings intensifying.

"If you'd asked me this a few years ago, I'd have said there are more important things for secularists to worry about," Charlie Klendjian, a commercial lawyer and secretary of the Lawyers' Secular Society, said.

"But then I started thinking about it more carefully, and I realised just how important this thing is... this isn't just a dispute about building a wall or whatever. It's about criminal justice."

Klendjian's worry is that jurors could be influenced by someone's religious views - from both sides, even "rabid anti-theists who think all those with religion are barking mad". He says everything is accentuated in a courtroom: "[The jury] will overanalyse things... and now you show this massive curveball in there called religion. It's like a bullet in the body, it does damage everywhere."

That damage will continue to take place indefinitely. For when the issue came to a vote the Magistrates Association - which represents three-quarters of England and Wales' magistrates - it was soundly defeated.

Still, the affair has shaken up those on both sides. Defenders of religion have been alarmed by what they see as growing pressure on the Bible's place in public life, while those wanting to accelerate that process have been left disappointed - and reminded once again of the extraordinary sticking power of religion in Britain.

"My own view is that it's lasted such a long time and it hasn't been queried until now," Labour backbencher Jim Dobbin, who signed up to the parliamentary motion opposing the change, said afterwards. His argument sticks in the throat but, for now, appears to have been decisive. "It's been accepted as part of the system," Dobbin added, "and therefore why change it?"