It is without doubt the most astonishing place in London. It’s an alternative reality. To enter the London Wetland Centre is like going through the looking-glass. You leave London and in a dozen strides you are out in the wild. Not in a green and tame park: a place that looks and feels and is wild. A dozen lapwings greeted me as I made the transition: lapwings! These are birds of misty marshes and soggy fields, birds that need a sense of space and open skies, but here they were, lapping their wings with the BT Tower behind them.

I went there when it was still Barn Elms reservoir: a bleak open cruciform expanse of black water with astonishing numbers of ducks. Birders used to go there in winter hoping for the elegant little ducks called smew. The place has been transformed. There are still plenty of ducks: but every square inch is now alive and throbbing with diversity.

Waterways, ponds, marshes, islands, reeds: this is a wild wet paradise created by human hands. It is just eleven years old, and opened to the public in 2000.

Everything about the place is startling. Marsh frogs chatter all around; a redshank, the classic marshland bird, made his triple-note call; a little egret glowed white from one of the shaggy islands; a great crested grebe carried grebelets on her back; a group of teal, perhaps the world’s most handsome duck, fed busily; reed and sedge warblers warbled away. A sparrowhawk, a chunky female, flew overhead.

And yet above us the planes roared in their endless head-to-tail passage to Heathrow and the traffic continued its white noise unceasing. The place is just 110 acres, but its brilliant incongruity makes a Tardis of it. It’s a separate world. Grass snakes, slow worms and water voles have been introduced. Bitterns drop by in winter.

The place is jumping with children: city kids who didn’t know there were such wonderful things in the world. They were expecting damn near 500 that day: and for them all, it would be a revelation. The best way to teach is not by telling but by showing: and the most effective way of looking after anything is not by means of duty but love. Love of the wild is the most important weapon in conservation, and this extraordinary place gives love a kick-start. But it’s not the answer. No one is pretending it is. The London Wetland Centre frequently gets official visitors from rapidly developing countries who imagine that the creation of such sites can make up for destroying everything else. That is not the case: and to believe so is to miss the point of both the wetland centre and of conservation.

High-profile tokenism is not a substitute for the real wild; instead, it is a wonderful bonus. London has always cherished its green places: earlier in the week, I walked through St James’s Park and Green Park; beyond the Wetland Centre lies Barnes Common, Wimbledon Common and Richmond Park. This really is a rich city.

The wildness of the wetland centre was not only established by humans: it needs constant management from humans. The intricate mixture of habitats needs careful control, or it would be lost – silt up, become overgrown, become dominated by invading vegetation, scrub up and dry up. Miracles like this need an awful lot of work. I was also shown a couple of orchids at the wetland centre. Orchids are rum things: rum in themselves, as they look too rich and elaborate to be wild British flowers, and rum also in the passions they arouse. They are the only plant that inspires a twitcher mentality: enthusiasts will travel miles to see a special orchid, and will seek them out with the voraciousness of a hunter.

I was shown a pyramidal orchid, a spectacular cone of pink, and also a bee orchid. This is a flower that looks as if a bee was sitting on it: but is a fake bee. It’s actually a flower pretending to be a bee, and it does so to attract male bees, which come down in a trance of horniness and roger the flower senseless before flying off laden with pollen, which they inadvertently spread after having been so soundly duped.

It is customary at this point to remark on the dim-wittedness of bees. Fancy getting sexually excited by something that’s not the real thing! Well, it’s just possible that one or two of my male readers can recall days when their passions were excited by mere photographs of naked women: and they’re not even three-dimensional.

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