The closer you get to Stonehenge, the smaller it becomes. In London or Hull or Hong Kong it looms large, up there in the imagination with the Great Pyramid and Teotihucan, throwing its monumental profile across our English psyche, embodying and obscuring everything we may not know about ourselves.

Stonehenge is our great-great-grandfather clock, our sun temple, our primal cathedral; erected in the murky pagan forest; surviving 3,000 years to dominate the Christian plain. This is Thomas Hardy's Temple of the Winds whose sombre hum, "like some gigantic one-stringed harp", lulled Tess of the d'Urbervilles to sleep on her last night of freedom, before her capture and execution.

Today's pilgrims find the stones on a traffic island in the fork of the A303 and the A344 so subsumed by the everyday might of modern traffic that they bring immediately to mind the 18-inch Stonehenge prop in Spinal Tap. It doesn't do much for the gravitas of a 40-tonne sarsen stone when, every minute, a lorry carrying that weight in MDF kitchen doors breezes past at 60mph.

And then there's the road underpass. Built for the best of reasons (to make the access route inconspicuous), it is vilified so much that it has come to symbolise Stonehenge's woes. This is because a subway is the most unenigmatic of things, which does not inspire visitors to ponder what they may not know about themselves, but, rather, awakens in them a sensation of being in Milton Keynes.

Yet Stonehenge is at least puzzle enough to draw 750,000 ponderers annually. English Heritage, which runs the site, is duty-bound to protect it from visitors who, at one extreme, would take bits of it back home to rockeries in Godalming, and, at the other, would indulge in sex rituals with underage goats, making the place stink of charred virgins. Which of these two groups most resemble Stonehenge's original devotees even the most sage of academics cannot tell us.

The modern visitor must view the stones, which are as mournfully isolated as elephants in a zoo, from an orbital gravel path. This is the closest to a trilithon as most people get, and from here it is small enough, if you hold out one arm and screw up one eye, to crush between thumb and forefinger.

This may save Stonehenge from 7,500,000 fingerprints a year, but it's a disaster for people. The temple is not an intellectual experience. We are not considering a Vermeer. The stones are the most tactile of artefacts, like Plasticine, utterly, irresistibly hands-on. You want to connect, to paint your children and dogs blue and run through them naked. You want to be part of the history, not merely someone standing on a gravel path in a raincoat. But it's not allowed. If you were to perform a sacrifice here (and, by some accounts, the site has an honourable tradition in this respect), you would have to do it on the gravel path, and even then I think it would be frowned upon.

Nobody can blame English Heritage. Everything it ever does here will be a compromise. No, to Hell with it: we can blame English Heritage. We can blame it for the visitor centre, in which Stonehenge enters a new concept of smallness, passing through the border control of Spinal Tap absurdity and straight out the other side. Here are Stonehenge teaspoons and Stonehenge fridge magnets and tiny Stonehenge models 5cm wide. Give me sex with a goat any day.