What do we want?

    Wallinger has been let loose on that huge, pompous, colonnaded exhibition space that runs down the middle of Tate Britain, named the Duveen Gallery in honour of its wicked benefactor, Joseph Duveen, 1st Baron Duveen of Millbank (1869-1939). Duveen was a crooked art dealer who specialised in flogging optimistically attributed Renaissance paintings to gullible American millionaires. I took against him with a passion when I saw what he did to the Elgin Marbles. Having paid for a new gallery at the British Museum to house them, Duveen decided the marbles weren’t pristine enough to fit his fantasy of Greek sculpture, so he locked the doors and brought in teams of workmen armed with Carborundum brushes to scrape off the surfaces and get them down to something whiter. His handiwork is still on show today. Sorry to go on about it here, but the Tate’s got me in a protesting mood, and that this cultural criminal should continue to be celebrated at the heart of Tate Britain — and, indeed, at the British Museum — sticks in the craw. And, while I’m at it, let us send the Elgin Marbles back to Greece.

    We clearly can’t be trusted to look after them properly.

    Anyway, the haughty suite of stone galleries Duveen gave to the Tate plays as important a part in Wallinger’s show as the things he’s put in them. Lofty, doomy, stony, grand, they are entirely unsuitable for the display of art and should really form the vestibule of a bank. They therefore provide a splendidly apposite setting for the scruffy line of placards, posters, banners, graffiti, traffic cones, tarpaulins and temporary fencing that appears now to be squatting in them. “Blair Lies, Kids Die!” howls a poster. “Baby Killers!” screams a banner. It’s as if someone broke in last night and did this.

    In fact, this air of casual protest is entirely artificial. A helpful text informs you that what you actually have before you is a detailed re-creation of the “wall” put up outside the Houses of Parliament by the protester Brian Haw, who began protesting about the sanctions imposed on Iraq in 2001. He is still there. In 2005, however, the government passed the Serious Organised Crime and Police Act, banning unofficial protest within a 1km radius of Parliament Square, and Haw’s ramshackle assembly of slogans, paintings, photos, home-made sculptures and letters from well-wishers, which had grown into a makeshift installation 40 metres long, was forcibly removed by 78 fearless coppers. These days, he’s allowed to protest only in a two-metre slot.

    There’s no doubt, of course, that Haw is a hero of our times, one of those potty and indefatigable political eccentrics who make you proud to be British. There’s something endemically crackers about his protest, and, from the Tolpuddle martyrs to the enchained suffragettes, this country has a glorious history of resolute naysaying to government policy. Free speech is precious on these shores. It’s disgraceful that Haw should be silenced by Tony B Liar.

    But quite what Wallinger is bringing to the table by re-creating Haw’s protest in such extraordinary detail is less clear. There’s nothing here that can be called great protest art, because that was never its point. Everything we see was produced to be waved at politicians, not to be in the running for the Turner prize. There are horrible photographs of mutilated babies, maimed and burnt in inaccurate missile attacks. And scattered among the home-made sculptures and angry slogans are nuggets of compelling information. Did I know that our parliament spent 700 hours discussing fox-hunting, and only seven hours discussing the war in Iraq? Actually, I didn’t.

    All this is salient, even effective. I was particularly moved by a battered white teddy holding a placard declaring “Bears Against Bombs”. It is also true that British art has a fine history of agitprop that goes back at least as far as Hogarth, who, providentially, has his own show opening at Tate Britain next month. Hogarth, who was never afraid of bluntness, would certainly have approved of the large photograph displayed here of Blair, Gordon Brown and Jack Straw washing their hands in bowls of Iraqi blood, underneath which is scrawled a quotation from Matthew’s Gospel about Pontius Pilate: “He took water, and washed his hands, before saying, I am innocent.”

    I rather suspect Hogarth would also have approved of Banksy, Britain’s best-known graffiti artist, who gave Haw a picture of two furtive squaddies painting a peace sign that was soon embedded in the tatty wall of protest. Banksy is now an expensive artist. Last year, Angelina Jolie spent £200,000 on his work. So, instead of responding to Banksy’s painting as a work of protest, I found myself imagining how much a Wallinger re-creation of a Banksy original might be worth. That’s the trouble with this setup. Instead of making you think about politics or protest, Wallinger’s installation directs you to issues of originality and authenticity.

    The exclusion zone around Parliament Square happens to pass through the middle of the Duveen Galleries, and half of Wallinger’s re-creation falls within it, while the other half doesn’t. A provocative black line on the floor marks this divide, and following it around is one of the more productive tasks prompted by the event. To see where it leads, I even went into the Clore Gallery, where all those Turners are lumped together so boringly. I haven’t been in there in years.

    Another of the rooms through which the exclusion zone passes contains a selection of war art by fine British artists from the past, notably Paul Nash. Staring at his Totes Meer, from 1941, a profoundly sad painting of hundreds of bits of broken fighter plane forming a dead sea of mangled metal, you see immediately what Nash brings to his protest and Wallinger doesn’t. It’s called heart.