When German-born photographer Emil Otto Hoppé wasn't busy with his day job - taking portraits of Marlene Dietrich, HG Wells or young Elizabeth Bowes-Lyon (better known to us as the Queen Mother) - he prowled the streets of London, shooting a city that seems as distant from our own as today's digital colour photographs are from the grimy monochrome of these prints.

It's the first third of the 20th century and London is filled with street urchins and eel boats, wondrously boxy cars and a plethora of hats. Flat caps, bowlers and trilbies abound, flagging up the social status of the men beneath them with wordless efficiency.

Architecture and clothing stand in contrast in these shots: we may recognise the building in Rendez-vous At The London Stock Exchange 1937 but the brokers, with their shiny top hats and three-piece suits, are alien and unknowable.

Hoppé is an artist as well as a witness; despite his limited palette and deliberately banal subject matter, he can and does extract drama from a pillar.

George Bernard Shaw watching a pavement artist or 1918 circus peformers relaxing in costume are no more exciting to look at than Kensington Gardens, shiny with winter rain in 1925; a pitifully small girl cleaning a 1934 pavement with a broom twice her size is treated with the same care for form as Big Ben's mighty clockface. Hoppé is a great talent - even bitchy Cecil Beaton called him "The Master".

Nor is the profundity of his images incompatible with humour: check the caption on the silhouetted man staring avidly at scantily-clad mannequins in a 1929 shop window and you'll have this fellow, Hoppé and the photographer's conflict between art and prurience all rolled into one. It's titled Studying Form.