An artist with the easy, breathless virtuosity of David Hockney occurs only a few times in each generation. His art is immensely pleasurable. The facility of line and stroke, the effortless anchoring of figures in pictorial space, lead the eye into a bright, condensed, stylised but wholly recognisable world.

It never fails to delight, and at the National Portrait Gallery��s exhibition of half a century of his portraits we read the contours of his faces and places with eager familiarity. Here is his lover Gregory Evans, whose limpid auburn beauty in ��Gregory Leaning Nude�� recalls a Florentine nobleman from Botticelli transported to the 20th century. The fashion designer Celia Birtwell is willowy and glamorous in pink neglig��e or black slip, or taut embodiment of 1970s chic in ��Mr and Mrs Ossie Clark and Percy��. Magnificently swelling to fill armchair, sofa, canvas, in ��Henry, Seventh Avenue��, ��Henry�� and the chilly conversation piece ��Henry Geldzahler and Christopher Scott��, the Metropolitan Museum curator, patron and flamboyant dresser surveys us quizzically, his broad domed forehead rhyming with his portly stomach.

Hockney makes friend