Variable geometry turbine

A variable geometry turbine comprising: a housing; a turbine wheel supported within said housing for rotation about a turbine axis; an annular inlet passage within said housing upstream of said turbine wheel and defined between respective radial inlet surfaces of first and second wall members; an outlet passage within said housing downstream of said turbine wheel; an array of vanes extending across the inlet passage, said vanes being connected to said first wall member; at least one of said first and second wall members being moveable along the turbine axis to vary the size of the inlet passage and/or at least one of said vanes being rotationally moveable about an axis that is substantially parallel to said turbine axis to vary the size of the inlet passage; wherein at least one particulate filter is provided within said housing at a location such that said particulate filter can be contacted by particulate matter flowing through said turbine during use.