It's possibly the most iconic and prolific image in fashion. Employed constantly by designers on t-shirts, jewellery, accessories and even shoes. A logo even more famous than that of Apple or Nike, sported by young and old, yet ultimately referring to an instrument of death and torture, and an ancient religion with which most wearers feel no direct connection. The popularity of the Christian cross in fashion is both perplexing and remarkable.

I'm not talking about cheesy t-shirts which people only wear to church and Christian events. This phenomenon is seen in high fashion – the very top designers, people like Versace, Ford and Gaultier. And inevitably, since the high street always takes their lead, the cross is proliferated across the shelves of every store from Abercrombie to Primark. The globally-recognised symbol of a faith apparently in decline in the West, is selling clothes on a scale that suggests consumers are far from offended or switched off by it.

This trend first started to surge in the early part of this decade, but a casual perusal of the local shopping mall reveals that it's certainly still in vogue. Shirts with enormous crosses covering front or back like a giant Celtic tattoo; diamante-encrusted accessories that give the humble rugged cross a slightly unsettling makeover. The continued appearance, season after season of products of this nature demonstrate one thing for sure: people are buying and wearing the Christian cross, and not because they feel a specific affiliation to its original owner.

For some, this is a worrying example of cultural appropriation, and one which deadens the true impact of the cross. Writing a forward to Graham Tomlin's 2013 book about the cross, Archbishop of Canterbury Justin Welby asked: 'Are we living with a symbol emptied of power by time and fashion?' He noted: 'For those early Christians it was a badge of shame. Today it is more commonly seen as a symbol of beauty to hang around your neck.' In another line much-quoted by the media at the time, he compared such jewellery to hanging 'a golden gallows or a tiny electric chair around your neck'.

In a way, of course, he's right. The empty cross, emblazoned with cheap crystals, is a long way from the devastating original icon and could potentially cause us to forget that this is a symbol of intense agony and eternal love. Yet I'm more hopeful. I wonder if the fashion industry is perhaps doing a marvellous marketing job for the Christian faith – if only we could embrace and harness it.

I spend a fair amount of time with young people and they seem to be the group who – more than anyone – are delighted to wear this somewhat mysterious spiritual symbol on their clothing. Many of them are living with what theologians have called 'the ruins of faith', perhaps knowing the name of the baby Jesus but unaware that Easter is about more than chocolate and a long weekend. They don't really know what the cross is, but they find themselves drawn to it, perhaps because they feel 'spiritual' and they understand that it at least carries that connotation. What's interesting to me is how ready these young people seem to be to have conversations around the icon they almost inadvertently bear.

That's the great opportunity that I think the cross in fashion presents. In most cases (unless they're being deeply satirical) those who choose to wear it have on some level already felt an affiliation to it. Whether on their shirt, jacket, ear or bag, they're carrying around a perfect natural discussion starter – if only we have the guts to ask them about it. In my experience, people are remarkably happy to talk to someone who starts a conversation with a compliment about their fashion sense.

Of course it's a large scale piece of cultural appropriation, but isn't that exactly what Paul did in Athens when he pointed to the Greeks' own religious imagery and subverted it for his own use? In Acts 17 the great apostle noted that the greatest minds and cultural pioneers of the day had built an altar to a God they didn't know. In some way, isn't that exactly what the emperors of high culture are now doing with a symbol they no longer understand, but feel drawn to?

We spend a lot of time bemoaning the fact that Christianity seems to be out of fashion in the West. In fact, fashion has taken Christianity to its heart. Rather than taking offence, perhaps we should follow Paul's lead and bring some  context to this altar 'to an unknown God'.

Martin Saunders is a Contributing Editor for Christian Today and the Deputy CEO of Youthscape. Follow him on Twitter @martinsaunders.