It's great to inflate

The original "bad boy" of American art, Paul McCarthy, 58, is famed for his visceral and theatrical explorations of the kitsch and grotesque aspects of life and consumer culture.

The tone of his work is exemplified by one video piece, Santa Chocolate Shop, in which, amid orgiastic scenes of consumption, Santa appears to defecate into the mouths of his elves. Yet, in an uncharacteristic display of taste and good humour, the Tate has invited McCarthy to deposit two new pieces, the largest inflatable sculptures in the world, outside the gallery.

Entirely black and 35 metres high, Blockhead, the larger sculpture, is a Pinocchio-style figure with a big square block for a head and a long, thin cylindrical nose, sitting on a pile of books in the middle of which there lies, inexplicably, a cave-like room where you can buy sticks of "Blockhead" rock.

Nearby, flopping obscenely in the wind, is the flesh-pink form of Daddies Bighead, a surreal depiction of a blob of ketchup rising from a bottle to assume anthropomorphic form, with spheres for eyes and a suggestive cone for a nose.

Typically, McCarthy's work is regarded as being dangerously trangressive in its fixation with taboo subjects, which credits the pieces with far more power than they actually have. Though mildy suggestive, these demented cultural forms derive their real impact from being funny and silly and a nice change from the usual pompous, po-faced stuff that passes for public art.