Fritz Hansen Series 7 Chair

The Series 7 chair is a single sheet of moulded wood on four thin steel legs. The shell rises from a broad, gently dished seat, narrows sharply at the waist and opens again into a rounded back, so that from the front it has the outline of an hourglass. The legs are chromed steel tube, splayed slightly and fixed to a small disc under the seat; they reach just beyond the seat's edge, so the chairs line up neatly in rows and stack.

It was designed in 1955 by the Danish architect Arne Jacobsen for Fritz Hansen, a Danish furniture maker founded in 1872 that had worked with him since 1934. Three years earlier he had drawn the Ant, a three-legged stacking chair made for the canteen of the Novo pharmaceutical works; Jacobsen credited the bent plywood of Charles and Ray Eames as a starting point. The Series 7 kept the Ant's idea, a light shell of laminated veneer pressed into a curve, and made it broader, steadier and four-legged.

It became one of the best-known chairs of its century. Its fame grew in 1963, when Lewis Morley photographed Christine Keeler sitting astride what looked like one; the chair in the picture was in fact a copy, but sales of the original rose after it was published. Jacobsen's Grand Prix chair followed for the firm in 1957, and the Swan and the Egg in 1958. Fritz Hansen has since added an armchair, an office chair, stools and upholstered versions on the same Series 7 shell.

The chair is still made only by Fritz Hansen, which counts more than five million produced. The basic model, number 3107, has a shell of nine layers of pressure-moulded veneer, available in natural woods, stains and lacquered colours, on chromed steel legs. It costs from £459 in Britain, and it is still the shape Jacobsen drew in 1955.