BICYCLING to Economist HQ each day, it is hard to miss the advertisments on double-decker buses, urging Britons who are not practising religious believers to tick the box marked "no religion" on the 2011 census, which is taken this month. The slogan is pithy enough: "Not religious? In this year's census say so."

The British Humanist Association is behind the campaign, and their website offers more detailed guidance.

Ticking "no religion", it says, is "better than answering with the religion you were brought up in if you don't believe in it anymore and don't think organised religion speaks for you." Addressing agnostics, it suggests:

If you are agnostic on the question of God but otherwise non-religious, we would say you should tick the ‘No Religion' box if you don't practise and don't believe that any religion can speak for you

It has advice for secular Sikhs and Jews, too, advising:

Writing in ‘secular Jew' or ‘non-religious Jew' in the religion section may be counted as being of the Jewish religion. The ethnicity question does not have a Jewish box but it does have an ‘any other white background' box which allows you to write in ‘Jewish.' Doing this and ticking the ‘No Religion' box in the religion section is therefore the best way to be counted as a non-religious Jew

and

UK law recognises Sikhism as both a religion and an ethnicity. If you are a practising Sikh, you can tick the ‘Sikh' box under the religion question. However, if you consider yourself ethnically Sikh but non-religious, writing in ‘secular Sikh' or ‘non-religious Sikh' in the religion section may be counted as being of the Sikh religion. The ethnicity question does not have a Sikh box but it does have an ‘any other Asian background' box which allows you to write in ‘Sikh.' Doing this and ticking the ‘No Religion' box in the religion section is therefore the best way to be counted as a non-religious Sikh.

Given that I am a secular sort, and would like a clearer separation between the church and state in Britain, I am slightly surprised to find I think the BHA's arguments are baloney, and even a little bullying.

I can understand why the BHA is making them. They think that modern Britain's strikingly secular character is not captured by census data reporting that a majority of Britons consider themselves Christian. They argue that this data is then used to justify public spending on faith schools, for example. That's baloney, too. The driving force behind government funding for faith schools [corrected, see comment below] has very little to do with religion, and rather more to do with the demand from middle class parents for more traditional, disciplined and/or cosy schools. Successive British governments have not protected faith schools because they fear an ear-wigging from Church of England bishops sitting in the House of Lords. It is because generations of ministers (a) know they would be lynched by voters if they closed down Church of England and Roman Catholic schools, which routinely top league tables and (b) send their own children to such faith schools (cf, Tony Blair, David Cameron and other well-known political parents).

But the BHA is unable to wish away one big problem. The census does not ask if British residents practise a religion or believe in a religion. Rightly or wrongly, it asks if they have a religion, and that is different. A non-believing Christian, Jew, Sikh or Muslim may well have a religion. And this is more than just wordplay.

For what it is worth, Bagehot is a lapsed Anglican, and it is hard to get more lapsed than that. That does not mean I have no religion. I lack faith. And that which I lack faith in is Church of England Christianity (a lesson drummed home with special force by living in non-Christian China for some years). I am marked, indelibly, by that which I do not believe. This being so, I would feel less than truthful if I ticked "no religion".