A turbine arrangement comprising: a turbine including turbine housing defining: a turbine cavity within which a turbine wheel is supported for rotation, a turbine inlet upstream of the turbine wheel, and a turbine outlet downstream of the turbine wheel; a flow passage between a location upstream of the turbine wheel and a location downstream of the turbine wheel configured to permit gas to flow from said location upstream of the turbine wheel to said location downstream of the turbine wheel without interacting with the turbine wheel; and a valve arrangement comprising: a valve member moveable between open and closed configurations, wherein in the open configuration gas may flow from said location upstream of the turbine wheel to said location downstream of the turbine wheel through the flow passage, and in the closed configuration gas is substantially prevented from flowing through the flow passage; a first actuator portion connectable to an actuator for moving the valve member between the open and closed configurations; and a second actuator portion in gas flow communication with a portion of the turbine arrangement upstream of the turbine wheel via an actuator gas passage; and wherein the turbine arrangement is configured such that gas may flow from said portion of the turbine arrangement upstream of the turbine wheel through the actuator gas passage to the second actuator portion, such that the pressure of said gas which flows through the actuator gas passage to the second actuator portion acts on the second actuator portion to urge the valve member towards the closed configuration. a turbine including turbine housing defining: a turbine cavity within which a turbine wheel is supported for rotation, a turbine inlet upstream of the turbine wheel, and a turbine outlet downstream of the turbine wheel; a flow passage between a location upstream of the turbine wheel and a location downstream of the turbine wheel configured to permit gas to flow from said location upstream of the turbine wheel to said location downstream of the turbine wheel without interacting with the turbine wheel; and a valve arrangement comprising: a valve member moveable between open and closed configurations, wherein in the open configuration gas may flow from said location upstream of the turbine wheel to said location downstream of the turbine wheel through the flow passage, and in the closed configuration gas is substantially prevented from flowing through the flow passage; a first actuator portion connectable to an actuator for moving the valve member between the open and closed configurations; and a second actuator portion in gas flow communication with a portion of the turbine arrangement upstream of the turbine wheel via an actuator gas passage; and wherein the turbine arrangement is configured such that gas may flow from said portion of the turbine arrangement upstream of the turbine wheel through the actuator gas passage to the second actuator portion, such that the pressure of said gas which flows through the actuator gas passage to the second actuator portion acts on the second actuator portion to urge the valve member towards the closed configuration. a valve member moveable between open and closed configurations, wherein in the open configuration gas may flow from said location upstream of the turbine wheel to said location downstream of the turbine wheel through the flow passage, and in the closed configuration gas is substantially prevented from flowing through the flow passage; a first actuator portion connectable to an actuator for moving the valve member between the open and closed configurations; and a second actuator portion in gas flow communication with a portion of the turbine arrangement upstream of the turbine wheel via an actuator gas passage; and wherein the turbine arrangement is configured such that gas may flow from said portion of the turbine arrangement upstream of the turbine wheel through the actuator gas passage to the second actuator portion, such that the pressure of said gas which flows through the actuator gas passage to the second actuator portion acts on the second actuator portion to urge the valve member towards the closed configuration.