There's not long to go, if David Meade, the Christian conspiracy theorist, has been reported correctly and is right: the Rapture is due on April 23. If ever there were a good time to max out the credit cards on a really comprehensive bucket list, it's got to be now: if you're really determined, you can cram a lot of living into a fortnight.

The thing is – of course – that he's wrong.

According to the Daily Express, which does tend to feature him fairly regularly, 'On April 23, the sun and moon will be in Virgo, as will Jupiter, which represents the Messiah.' This has something to do with Revelation 12: 1-2, which is about the 'woman clothed with the sun', and Meade offers a few more astrological titbits about Leo, Jupiter and the (entirely imaginary) planet Nibiru, which apparently is due to appear on that day. It isn't quite clear what the Rapture – when believers are supposedly whisked away from the earth – has to do with it, but that might be a little headline-writer's licence.

If all this sounds a little vague, it's not entirely Meade's fault. His Planet X website is full of carefully-worked calculations and prophecies; it's just that to refute them point by point would take longer than this writer probably has left (which if by some extraordinary chance he's right, is not long at all). But his 'prophecies' continue to fascinate. Nibiru (which NASA has never been able to find) was supposed to collide with the earth in September last year, then October; then it was supposed to be the just beginning of a seven-year period of tribulation. He sort of covers himself on his website with a tirade against misreporting by the mainstream media and saner-sounding advice not to 'do anything crazy like selling your house', but the direction of travel is clear: it's all happening, folks.

And here's the thing: David Meade might be a bit off the scale when it comes to this kind of thing, but he's drawing from a well that supplies plenty of other writers too. There's a whole genre of rapture-writing that began in modern times at least with Hal Lindsey's notorious The Late Great Planet Earth (1970). It's all based on the same premises: that the book of Revelation is a coded account of the future of the earth, and that pre-millennialism provides the key to the code. There will, according to this view, be a literal reign of Christ on earth for a thousand years. There will also be a 'rapture', when Christians will be caught up to heaven, and a Great Tribulation. The order of these events is disputed (there are pre-tribulationists, post-tribulationists and mid-tribulationists, for instance) – but it's all there in the code, if you know how to read it.

In large sections of the evangelical church, especially in the US, this has become orthdoxy. It's just the details we have to sort out.

And if there's one thing that's sure, it is that the writer of Revelation, John, would have been absolutely astounded by most of what's been written about his book. Because another way of looking at it is to say that it's not really about the future at all. It describes the present, in vivid metaphors and images, and if it describes the future it's only in terms of the consequences of sin and the abuse of power in every generation.

If Christians insist on reading it like the entrance test for the security services, they'll miss what it's really about – and they'll be distracted from the real work of the gospel.

Just a couple of weeks ago was the 50^th anniversary of the death of Martin Luther King. And in the last sermon he preached, the night before he was shot, he drew on Revelation imagery and said: 'It's alright to talk about "long white robes over yonder", in all of its symbolism. But ultimately people want some suits and dresses and shoes to wear down here. It's alright to talk about "streets flowing with milk and honey", but God has commanded us to be concerned about the slums down here, and his children who can't eat three square meals a day. It's alright to talk about the new Jerusalem, but one day, God's preacher must talk about the New York, the new Atlanta, the new Philadelphia, the new Los Angeles, the new Memphis, Tennessee. This is what we have to do.'

Any reading of the Bible that isn't earthed in the reality of life in the here and now is a false gospel – and that's what this reading of Revelation has become. It's not enough to refute people like David Meade (who is, let's face it, an outrider) point by point; it's time to rethink the whole way Revelation is read.