Variable geometry turbine

A variable geometry turbine comprising a housing 2, turbine wheel supported in the housing to rotate around an axis, an inlet passage 11 extending radially inwards towards the turbine wheel, a cavity 25 provided in the housing and a moveable wall member 12 at least partially received in the cavity, the cavity being defined by radially inner and outer surfaces which are curved and a base surface arranged between them, the moveable member being moveable towards and away from the base surface of the cavity, where it extends into the inlet passage and changes the axial width of the passageway, the moveable wall including a plurality of axially extending apertures 32,33 which allow fluid communication between the inlet passageway and the cavity, the moveable wall has radially inner and outer flanges which extend from the annular wall, where the base of the cavity matches the inner surface of the moveable member to reduce dead space in the cavity. Also included are claims for a turbocharger which includes the variable geometry turbine and a method of forming the variable geometry turbine.