A delivery system for deploying a self-expanding tube into a blood vessel, comprising: a tubular member configured for insertion into the blood vessel; an elongate body extending within a lumen of the tubular member; and a self-expanding tube positioned radially between the tubular member and the elongate body, wherein: over at least 50% of the length of the self-expanding tube, at least a portion of the self-expanding tube engages outwardly with the tubular member and inwardly with the elongate body; a longitudinal engagement force acting between the self-expanding tube and the tubular member and a longitudinal engagement force acting between the self-expanding tube and the elongate body are such that, during all stages of deployment of the self-expanding tube in use by longitudinal retraction of the tubular member relative to the elongate body, there is substantially no relative movement longitudinally between the elongate body and any portion of the self-expanding tube that remains in engagement with the elongate body; the self-expanding tube is configured to self expand from a radially contracted state to a radially expanded state in a process involving longitudinal shortening of the self-expanding tube relative to a longitudinal axis of the tubular member; and the elongate body is configured to self expand from a radially contracted state to a radially expanded state in a process involving longitudinal shortening of the elongate body relative to the longitudinal axis of the tubular member, the elongate body is formed from a material having a shape memory property, characterised in that the elongate body is configured to self-expand and longitudinally shorten by switching from a state in which a longitudinal axis of the elongate body is parallel to the longitudinal axis of the tubular member to a state in which the longitudinal axis of the elongate body is not parallel to the longitudinal axis of the tubular member due to shape memory forces. a tubular member configured for insertion into the blood vessel; an elongate body extending within a lumen of the tubular member; and a self-expanding tube positioned radially between the tubular member and the elongate body, wherein: over at least 50% of the length of the self-expanding tube, at least a portion of the self-expanding tube engages outwardly with the tubular member and inwardly with the elongate body; a longitudinal engagement force acting between the self-expanding tube and the tubular member and a longitudinal engagement force acting between the self-expanding tube and the elongate body are such that, during all stages of deployment of the self-expanding tube in use by longitudinal retraction of the tubular member relative to the elongate body, there is substantially no relative movement longitudinally between the elongate body and any portion of the self-expanding tube that remains in engagement with the elongate body; the self-expanding tube is configured to self expand from a radially contracted state to a radially expanded state in a process involving longitudinal shortening of the self-expanding tube relative to a longitudinal axis of the tubular member; and the elongate body is configured to self expand from a radially contracted state to a radially expanded state in a process involving longitudinal shortening of the elongate body relative to the longitudinal axis of the tubular member, the elongate body is formed from a material having a shape memory property, characterised in that the elongate body is configured to self-expand and longitudinally shorten by switching from a state in which a longitudinal axis of the elongate body is parallel to the longitudinal axis of the tubular member to a state in which the longitudinal axis of the elongate body is not parallel to the longitudinal axis of the tubular member due to shape memory forces. over at least 50% of the length of the self-expanding tube, at least a portion of the self-expanding tube engages outwardly with the tubular member and inwardly with the elongate body; a longitudinal engagement force acting between the self-expanding tube and the tubular member and a longitudinal engagement force acting between the self-expanding tube and the elongate body are such that, during all stages of deployment of the self-expanding tube in use by longitudinal retraction of the tubular member relative to the elongate body, there is substantially no relative movement longitudinally between the elongate body and any portion of the self-expanding tube that remains in engagement with the elongate body; the self-expanding tube is configured to self expand from a radially contracted state to a radially expanded state in a process involving longitudinal shortening of the self-expanding tube relative to a longitudinal axis of the tubular member; and the elongate body is configured to self expand from a radially contracted state to a radially expanded state in a process involving longitudinal shortening of the elongate body relative to the longitudinal axis of the tubular member, the elongate body is formed from a material having a shape memory property, characterised in that the elongate body is configured to self-expand and longitudinally shorten by switching from a state in which a longitudinal axis of the elongate body is parallel to the longitudinal axis of the tubular member to a state in which the longitudinal axis of the elongate body is not parallel to the longitudinal axis of the tubular member due to shape memory forces.