My attention has been drawn to latest results on the long-running statistical survey of British attitudes to religion carried out by King's College, London. You can find summaries of it here and here.

The results aroused some comment in the press but were largely seen as simply confirming trends that had long been obvious. Nevertheless, as an evangelist, I found it interesting and on reading it I found myself with four reactions.

First, hesitation. Are any facts more unreliable than statistics on religious beliefs? In my experience, the beliefs of many people today about God are both vague and changeable. The lack of clarity here is worsened by the fact that this survey was first carried out in 1981 and the price of its valuable longevity – this is now its seventh appearance – is that the questions were framed in the long-vanished world of the early 1980s.

Take for instance a key question: 'Do you believe in God?' When first written this was straightforward because a national 'benchmark' existed for God: he was the Christian figure, defined with some precision by the Church of England. Not so now. In today's multicultural society, where every manner of belief and unbelief coexists, the word 'God' demands a definition. So, for example, I have no idea who or what 'New Agers' consider God to be and sometimes I'm not sure that they know either.

Here's another question with inbuilt confusion: 'Do you believe in life after death?' Please, what kind of life? Some glorious physical body as envisaged by traditional Christianity? Some vague, see-through, ghostly spirit? Reincarnation as a rabbit? There are many other areas where clarification is desperately needed: 'prayer', 'religious', 'religious attendance', etc.

There's a broad-brush, coarse-grained nature to the survey that undermines confidence.

Second, consternation. For all my hesitation, I have no doubt that there is valuable data here. But what ultimately does it mean? Many figures raise questions. So, for instance, the survey notes a growing number of people who say they are atheists. Now, is this a genuine conversion to the hard, barren creed of atheism or merely that it is now socially acceptable (indeed fashionable) to admit to being an atheist?

And what on earth (or in heaven) lies behind the fact that while belief in God seems to be in decline, beliefs in an afterlife, heaven and hell are either surviving or even thriving? A post-mortem eternity without a just or loving God is not just illogical but scary. Who decides who goes to heaven or hell? On what basis? Who (or what) determines who we share heaven with? There are some people I'd be reluctant to sit next to on a long-haul flight let alone spend eternity with. I think what we are seeing is an illogical, and indeed incoherent, longing for all the benefits of traditional religion without any relationship with God, which is at its heart.

Third, frustration. With a few exceptions, these are not encouraging graphs for the Christian church; line after descending line depicts the tide going out on any public faith. The forty-year timescale of these surveys covers my own ministry as an evangelist and I am frankly frustrated – there are stronger words – by the failure of many of the Christian churches to have made any substantial impact during this time.

It's been obvious since at least the Second World War that evangelism was desperately needed in Britain and yet, with some wonderful exceptions, little has been done. These sad graphs bear harsh witness to generations of church leaders who have either ignored the gospel, distorted it or simply failed to preach it. Here is a sombre testimony to the shepherds failing the sheep and allowing wolves in.

Finally, however, I have anticipation. There are some oddities here that give cause for hope. For one thing, Generation X, Millennials and Generation Y are showing signs of bucking various long-term trends. For another, I know that for all the decline in overall numbers there are many places where the church is growing in strength and depth. Numbers are not everything. I believe we are seeing a shift from a church comprised of many people with limited motivation to one made up of fewer but more motivated members.

Finally, those continued beliefs in heaven, hell and the afterlife, which gives the lie to the idea that everybody is becoming an atheist, are suggestions that people are longing for something beyond what secularism or materialism can offer. In Ecclesiastes 3:11 we read that God has 'set eternity in the human heart'. In the wilderness of this world, people are hearing rumours that beyond the here and now, is light, hope and life.

There is no cause for complacency in these figures. There can be no disguising the fact that there is a fundamental problem in British Christianity. Every church minister and indeed every Christian must ask themselves two questions. First, am I giving evangelism the priority that it desperately needs? Second, am I praying for revival? With action and prayer and in the providence of God and the working of his Spirit, it may be that the gloom we are in may not be that of sunset, but dawn.

Canon J.John is the Director of Philo Trust. Visit his website at www.canonjjohn.com or follow him on Facebook, Instagram or Twitter.