From the moment when in the early 1850s its patterned walls first rose above the monotonous stock-brick streets north of Oxford Street, All Saints’ Margaret Street (Fig. 1) has been recognized as a building of exceptional originality and significance. Long before its interior was finally completed for consecration in November 1859, the church was illustrated and applauded in the architectural press (Figs 2 and 4). Subsequent critics, from Eastlake and Bumpus and Muthesius to Summerson and Hitchcock, have all acclaimed it as a turning point,‘a bold and magnificent endeavour to shake off the trammels of antiquarian precedent’ which had fettered the early Victorians, ‘in many ways the most moving building of the century.’ Even so, the critics have always been puzzled by All Saints'. How did this revolutionary building come to be designed as the model church of the Ecclesiological Society, whose concern had hitherto been the strict observation of English medieval precedent ? How, indeed, does it fit into the Victorian Gothic Revival? Does it represent the influence of Rus-kin? If, as Professor Hitchcock and Sir John Summerson both conclude, its revolutionary features are due to its architect, William Butterfield, did he get the ideas through travelling, or reading, or did he invent them? Are the faults in the building, as well as its powerful inventiveness, due to naïve ignorance and an inability to co-ordinate the work of fellow artists, or to a deliberate and sadistic hatred of beauty? Finally, what is the real aesthetic effect of this building : certainly it is fascinating, but is it fascinatingly beautiful or fascinatingly hideous?