A grand old man gets his abstracts out for the boys

Terry Frost | Royal Academy, London

Call me an old prude if you like, but what is it with the British and breasts? Walk into the Royal Academy's retrospective of Terry Frost's 60-year career and you'll see them everywhere.

Call me an old prude if you like, but what is it with the British and breasts? Walk into the Royal Academy's retrospective of Terry Frost's 60-year career and you'll see them everywhere.

On the left of the door to the second room, there's a small but disproportionately annoying collage piece called Laced Grace prototype (1962), a semi-abstract portrait of the kind of bustier worn by Barbara Windsor playing Nell Gwynne in Carry On films. Across from this is SS99 (1963), another take on the same subject but in a larger cup-size. Next to that is a painted plywood wall-sculpture which suborns the rarefied aesthetic of Russian Constructivism to suggest a pair of bosoms called, dear God, Mae West (1965). ("I called it Mae West because it's big at the front," reveals a candid Frost in the catalogue to the show.) And finally, and to this critic's austere little mind at least, most irritatingly, there is a large abstract canvas called Red, Black and White (1967): another Soviet evocation of - you guessed it - a pair of buzzies, Kasimir Malevich meets Beryl Cook.

Now, there's nothing wrong with breasts in art per se. Pound for pound, they are probably the most frequently depicted portion of the human anatomy: think of Rubens, whose work the 85-year-old Frost spent much of his youthful art studentship copying. Nor, I suppose, is there any particular reason why abstract artists shouldn't find breasts as legitimate a subject for painterly jeux d'esprit as any other kind of painter. Pollock's work is charged with sexual fervour, Victor Pasmore's, in its British way, even more so.

The trouble - or, these things coming in twos, the pair of troubles - is the breastliness of Frost's breasts. Walk around the Academy's show and you will sense the underlying problem. Frost is a masterly painter, occasionally a brilliant one. His early work, made in the 1950s, shows a real sense of the drama of the dialogue between paint and canvas. A picture like Black and White Movement on Blue and Green II (1951-52), shaped by Frost's response to Russian Constructivism, is all about reinventing abstract geometry as a stand-in for weight and balance: the relationship between the boat shapes in Frost's canvas is the same as that between the elements in a Tatlin stabile. Added to this rather rarefied recipe, though, is a slug of English romanticism visible in the work's muted colourism and thin but hand-hewn scumbled glazes. It is Russia with a human face, an art that is not merely admirable but likeable.

To wax gossipy for a moment, it is not entirely irrelevant that the opening party for Frost's retrospective should have been attended by his fellow old Trot, Denis Healey. (That Gordon Brown was also there you may make of what you will.) Frost makes no bones about the fact that his youthful fondness for Constructivism was shaped by an equally deeply-felt belief in Communism. A picture like Red, Black and White, Leeds (1955) is not just an artistic manifesto but a political one. Like Black and White Movement, its abstraction is not simply emotional but in some way moral.

Which, unfortunately, is where the breasts come in. Some time around 1960, the fire in Frost's political belly would seem to have slipped southwards. From Laced Grace on, he spent the 1960s as the Ma Larkin of British abstraction: earthy in a way that one suspects the artist himself would probably have described as fecund and/or life-affirming. Another way of putting it would be to say vulgar. This really isn't prudishness: it's simply that Frost is a very good political painter and an appalling comic one. It is the juxtaposition in this show of fine, serious abstract pieces like Force 8 (1960) with dogs like Laced Grace that make you wince at Frost's squandering of his own talent. And seeing the 1967 Red, Black and White - a work that I've always thought of as one of the high points in British abstract painting - in this mammary context is like hearing Benjamin Britten played on a kazoo. Can this piece of Constructivist abstraction really be just a particoloured bosom? You begin to wonder.

Which makes the testosteronal fading of Frost's old age come as something of a relief. The worst thing you can say about the pictures in the last part of his show is that some of them look dated; the best, that some - and notably a collage piece called True Blue (1975) - recapture the poise and seriousness of his early work. As with Frost's chosen subject, size isn't everything: a smaller and more selective show would have served him better.

Terry Frost - Six Decades: Royal Academy of Arts, W1 (020 7300 8000) to 12 November