Perhaps it was the effect of the elaborately mosaicked and marbled stage of the Wigmore Hall, but when a black-clad Thomas Zehetmair stepped out last night to occupy this space with just his violin and Bach for company, the image was incongruous. Even devotees of the hall will surely acknowledge the fussiness of its aesthetic appeal, the lingering visual excesses of a bygone age making it as unlikely a setting for Zehetmair’s deconstructed style as for the sharp architectural edges of Bach’s Sonatas and Partitas for Solo Violin. Yet host them it did, and in a characteristically uncompromising performance, Zehetmair managed to bring his comfortably sat audience along with him into an altogether less warm and secure place.