Terence Blacker: Count me out of the white horse fan club

It is a wonderful joke. It is folk art, like maypoles and cheese-rolling. It is a celebration of our history. It fuses the art of Magritte with that of the great 18th century painter George Stubbs. It is a patriotic symbol, which will remind those who arrive in Britain aboard the Eurostar of this island's glorious past.

This much must be conceded to Mark Wallinger's "Horse", the 160ft structure which has just been awarded £2m of public money. It has provoked reactions – all of those in my first paragraph are from respectable newspapers – every bit as faddish and ill thought-out as the project itself. "In a New Labour age when Britain's history and heritage is [sic] so derided, how refreshing it is to see that Wallinger is celebrating both with this public monument," Sir Roy Strong has written in a moment of sublime silliness.

My confident prediction is that, if this concrete and fibreglass construction is built and stays up for any length of time – and it would be a foolish gambler to place money on that – it will come to represent not heritage or history but the sort of lazy, metropolitan thinking which has settled on early 21st century Britain like grey slush.

Public art can be noble and uplifting: Anthony Gormley's "Angel of the North" is a feat of engineering and creativity which celebrates, on an appropriate scale and in the right medium, the great industrial past of the north of England. "Horse", a rather obvious gesture of me-tooism by the south, may indeed be a joke but it is one which mocks not only the public but also any art which dares to be figurative and interpretive rather than conceptual.

The £2m commission seems to have been granted on the basis of a photomontage, a photograph of a large horse placed on a small landscape, and a plastic model not dissimilar to a My Little Pony toy.

The very naffness of the design is apparently wittily self-conscious. Here is a fan of the project, Mark Hudson, writing in The Daily Telegraph. "What we actually have is a generic, static image taken from a child's farmyard set.... Where once modern art was an in-joke shared only by a tiny cognoscenti, now we're all in on it."

Yet the joke makes serious claims for itself. According to Wallinger, the horse is a symbol of import-export and immigration. "It has a bridle on it to suggest we had some kind of input." This explanation feels tacked on, fraudulent – and not only because the horse is not in fact wearing a bridle at all, but a head-collar. So much for attention to detail.

Mix heritage and history and you get horse; then make it very, very big. That is the concept behind this work of conceptual art. It represents a view of landscape as seen from the bar of the Groucho Club. In reality, the beauty of the English countryside (and, indeed, the beauty of a horse) is created by proportion and balance. Wallinger's structure, which will be seen for miles, is a living mockery of that idea.

Great practical jokes have been played on the public by dangerous, funny outsiders, from Spike Milligan to Chris Morris. But "Horse" reveals the rather less amusing prospect of the Establishment playing an in-joke on itself, and with public money. In the event that it does actually go up and stay up, the fibreglass and concrete horse may indeed be seen as a symbol of Britain for those entering the country. It is what it symbolises which is worrying.

Some dodgy adults need to grow up

Stories of adults behaving oddly towards children are not hard to find. The octo-mum Nadya Suleman, who loves children so much she has just had eight more to add to her first six, has set up a website on which she asks for donations. An Episcopalian minister has posed his two sons on the chimney of his two-storey house to get a good photo for the School Book Week.

Riding high in the list of dodgy adults must be the people at Channel 4 who are responsible for the new reality show Boys and Girls Alone. The set-up is simple: isolate two groups of children from adults, and let the cameras roll. If there is not enough unhappiness, give the two groups of children £400 each. If one girl is found to be upset about her parents' divorce, film a tearful meeting with her mother.

Already, of course, there have been rows, tears, gangs and bullying. Why is this is seen to be a responsible way to treat children – even in the sacred name of TV entertainment?

Harmony on Lord Howe Island

Human behaviour on the Galapagos Islands is "a parable of how we treat the natural world", Sir David Attenborough has said. He might have mentioned that another island grouping, also blessed with rare endemic species and a fragile ecosystem, is already showing how tourism and wildlife can flourish together. On Lord Howe Island, 370 miles off eastern Australian, tourists are limited to 400 at one time and full-time residents to 320. There are no big hotels, no large-scale tourist developments – no concession to greed, in fact. The result is a sort of harmony between the human and the natural worlds.