Two versions of Richard Hamilton's Swingeing London are on show in two exhibitions in London: at the Hayward Gallery's The Painting Of Modern Life, and now, less convincingly, at the National Portrait Gallery's Pop Art Portraits.

The 1967 canvas shows an image of Mick Jagger handcuffed to art dealer Robert Fraser, both having been arrested on minor drugs charges. Their faces are obscured by raised hands and the work is more social critique than an exploration of image or personality. So on both counts, you might think it an odd inclusion in an exhibition on portraiture.

But then Pop Art Portraits is full of oddities, even more so with Hamilton's seminal 1956 photocollage Just What Is It That Makes Today's Homes So Different, So Appealing? The work may contain a few advertising-related mugshots but how the curators thought it qualified for the portrait department is unclear. The same could be said about the abstract blurs of Interesting Journey by Allen Jones.

Quibbles about genre-crossing aside, this is still a limp survey. Featuring a host of British and American pop artists, the Brits are largely put in the shade, with much of the best work belonging to Andy Warhol (his Double Elvis beats everything else). Still, Pop Art Portraits does present an oxymoron. The movement was, after all, more about celebrating surface than going beneath the skin.

Until Jan 20, National Portrait Gallery, St Martin's Place, WC2, daily 10am to 6pm (Thu and Fri to 9pm), £9, £8 and £7 concs. Tel: 020 7306 0055. www.npg.org.uk Tube: Leicester Square/Charing Cross