A variable geometry turbine comprises: a turbine wheel in a housing assembly defining a radial gas flow inlet passage; an annular wall member which is displaceable to control gas flow through the inlet passage; and a linkage mechanism comprising at least one actuating member operably connected to the annular wall member to control displacement of the wall member. The actuating member has a terminal portion defining a radially extending flange and extends in a direction substantially parallel to the turbine axis through an aperture defined by a retaining member to locate the radially extending flange in between said retaining member and annular wall member. The terminal portion is contacted by the retaining member to connect the actuating member to the annular wall member. The aperture defines a clearance to accommodate displacement of the retaining member relative to the actuating member.