A church in Bristol has hit the headlines after it gave notice to a yoga instructor who had been using its hall for the last nine years. Naomi Hayama was told by leaders at St Michael and All Angels in Bristol that she would have to leave because yoga's roots "lie in thinking that is not compatible with the Christian faith". She is not happy, and neither are her students.

I don't understand. What has Christianity got against fermented milk?

Yoga is an ancient spiritual and physical discipline originating in India, and has nothing to do with yoghurt. There are different schools and practices, some of which are much more physically arduous than others. It was introduced to the West in the 19th century and became widely popular in the 1980s.

Ah, yes – you need to be able to wrap your leg around your neck.

Some practioners do, but it is not obligatory. Many poses or 'asanas' are much less demanding, and beginners are encouraged to take things gently. The emphasis is on graceful fluidity of movement, controlling the breathing and developing flexibility and balance.

It sounds harmless enough.

Most people would say so. However, some Christians are uneasy because it is rooted in an Eastern philosophy which is independent of Christianity. The word is Sanskrit for 'union' and the philosophy teaches that: "Its objective is to assist the practitioner in using the breath and body to foster an awareness of ourselves as individualised beings intimately connected to the unified whole of creation." Its five 'yamas', principles for dealing with people around us, are: non-violence, commitment to truthfulness, non-stealing (broadly understood), moderation and self-control, and non-grasping (letting go of our attachments to things).

That does sound a bit religious.

Yes, and many Indian practioners are very sniffy about Westerners who think it's just a good way to lose weight or de-stress. However, the British Wheel of Yoga says categorically: "Yoga is not a religion. Most classes provide a healthy balance between philosophy and asana practice and it is up to the individual as to whether they take the philosophy on board."

So this is where it gets complicated.

Yes. The question is whether you can detach the physical and mental aspects of yoga from its spiritual origins. For most Western practitioners, the answer is "of course you can"; it has no religious connotations for them at all. Some Christians say that whether they realise it or not, they are tapping in to something which is fundamentally opposed to Christian understandings of God, the world and the nature of human beings. Some also believe that there are spiritual forces at work intent on deceiving people into thinking there's no danger, when there actually is.

Hence the decision to kick out the yoga club in Bristol.

Indeed. The church said in a statement: "We are aware that yoga can be practised as either an exercise class or as a spiritual discipline and anywhere in between, however we understand that its roots lie in thinking that it is not compatible with the Christian faith and the Christian faith has not appropriated yoga."

You say, "some Christians". So not all, then?

Indeed not. There is a Holy Yoga movement which is a Christian version, and a PraiseMoves network which does the same sort of thing but eschews the name. These movements are specifically designed to contrast with yoga 'proper', though they are of course criticised by some Christians who think it's all a bit dodgy.

Bluntly, it all seems like a bit of an over-reaction. I'm not as flexible as I was; would it really do me any harm?

Many Christians would say not. If you don't want to buy in to the philosophy, you don't have to. Doing yoga doesn't make you a Hindu or a Buddhist any more than singing along to George Harrison does.

There are more fundamental points, though. Evangelistically: most people don't do yoga for the spiritual side, but if they are spiritual seekers, you'd think that having them on church premises would be a really good thing. Rather than seeing them as the enemy, wouldn't it be better to see them as children of God who don't have a relationship with Him yet, rather than alienating them? And spiritually: what exactly are churches that take this line afraid of? There is one God. He has no rivals. The idea that there is anything so sinister in a yoga class that large numbers of people need to be alienated by evicting it seems just a little odd.

And Yogi Bear?

No relation.