A catheter (10) includes a handle (12), a catheter sheath (14) and a stylet having a shaped distal part received within the catheter sheath (14). The catheter (10) includes a catheter shape release mechanism comprising the catheter handle (12) and an elongate catheter sheath carrier (30). The catheter sheath carrier (30) is slidable between a first position in which the shaped distal part of the stylet lies in register with the distal part of the catheter sheath (18) to impart that shape to the catheter sheath (14) and a second position in which the shaped distal part of the stylet is located proximally (80) of the distal part (18) of the catheter sheath. The catheter shape release mechanism enables retraction of the handle (12) and the stylet (20) whilst keeping the catheter sheath (14) in place in case the catheter snags on tissue when in use.
