The idea of children being allowed to carry knives while at school sounds like a red rag to a bull. But that is what Sir Mota Singh QC, Britain’s first Asian judge, who is now retired, says should be allowed. Not any old knife – but the ceremonial dagger known as the Kirpan.

The Kirpan is one of five “articles of faith” which also include Kesh (unshorn hair) and Kara (steel bangle) that are worn by practising Sikhs.

Given the UK’s well-publicised problem with knife crime, his suggestion is controversial. It raises the question of how far society should “bend the rules” to accommodate people who wish to practise a religion.

Toleration, equality, and respect for others are important values in Britain today. Indeed, it seems unlikely that any multicultural society could be harmonious without them. Even so, the balance between them can be easily upset. Respecting the views of one group in society by allowing them special privileges can seem like favouritism, and this can foster resentment and undermine toleration.

So, how much freedom should people have to live the way they want to live?

The political philosopher John Rawls believed that everyone should have the maximum amount of freedom compatible with everyone else having the same amount. In other words, we should be free to act as we please, provided that our doing so does not restrict the freedom of others.

This principle – with its commitment to both equality and liberty – underpins much UK legislation. For example, car owners living in built-up residential areas often face restrictions on how many cars they can park on the street, since there is not enough space to allow unlimited parking for everyone.

Religion v football

Another influential view is that of John Stuart Mill, who argued that, in disagreements about whether or not a certain activity should be permitted, the burden of proof rests with those who favour restricting the activity.

In liberalised societies like the UK, activities are generally restricted only with good reason, usually because they pose a significant risk of harm to others.

So, for example, driving while drunk is illegal because of the increased risk of injuring someone. On the other hand, restrictions on activities that do not pose a risk of harm to others – such as restrictions on sexual activity between consenting adults – tend to be controversial.

Applying Rawls’s principle to the case of Kirpan-carrying, it turns out that if Sikhs are to be permitted to carry them, then everyone else should be permitted carry knives too. However, to relax the restrictions on carrying knives in this way would raise the risk of knife injury for everyone.

This risk of harm to others justifies restricting Kirpan-carrying by Sikhs and everyone else, in much the same way that many other potentially harmful activities are restricted.

So, it seems sensible not to allow anyone and everyone to carry a knife.

Is religion special?

Currently, however, there is an exemption – under the Criminal Justice Act 1989, people are allowed to carry blades for religious reasons.

But, is it right that they should be exempt?

To answer this, we must consider whether a person’s religion justifies their being allowed to behave in a way that others are not allowed to behave. What is special about religion?

Well, a plausible answer is that practising a religion is central to the well-being of many people and communities – therefore, we should not curtail the freedom to practice religion without good reason.

However, this could be unconvincing as a justification for allowing Sikhs to carry Kirpans. Many non-religious activities are also central to the well-being of many people and communities, and yet such activities are frequently and uncontroversially restricted.

For example, playing musical instruments is centrally important to the lives of many people, yet we do not allow people to play their instruments loudly in residential areas in the middle of the night. And playing football is important to many people, yet football games are not permitted on busy roads, in shopping centres, on other people’s property without their consent, and so on.

The reason these activities are restricted brings us back to considerations of harm: unrestricted freedom for musicians and footballers to practise their chosen activities would cause harm to others.

Of course, religious people may argue that religion plays a far more important role in their lives than music or football play in the lives of those who enjoy these activities, and that as a result, special efforts should be made to accommodate religious practices.

However, not only is this claim difficult to verify, but giving religious people privileges denied to non-religious people goes against the commitments to equality and respect for others, both of which are important values in Britain today. Practicing religion, then, should be subject to the same standards as non-religious activities.

Religious cannabis

That is, those who wish to practise religion should be free to do so, but they should not be permitted to engage in activities that pose significant risk of harm to others. Relaxing the restrictions on carrying knives would pose such a risk of harm by increasing the risk of knife injuries. As a result, it seems reasonable to restrict the carrying of Kirpans.

On the other hand, the Millian view that activities should not be restricted without good reason calls into question current restrictions on all sorts of other practices, religious and otherwise. It is not clear, for example, that planned French restrictions on Muslims wearing full veils can be justified; nor is it clear that Rastafarians (and others) should be prevented from smoking cannabis. Cannabis is a holy herb of Rastafari religious ritual, yet in Britain it is illegal.

On this view, even many apparently innocuous restrictions – such as the restriction that many workers and schoolchildren should wear uniforms – may turn out to be unjustifiable. It is not always obvious whether or not an activity is potentially harmful, and so deciding which activities should be restricted is not always a simple matter.

For example, whilst the French government sees burqa-wearing as undermining the freedom of women, this view is controversial and many disagree that it justifies restricting the freedom of people to dress as they please.

However, in cases where it is clear that an activity is potentially significantly harmful – and Kirpan-carrying seems to be just such a case – failing to restrict it is difficult to justify.