Electrosurgical resector tool

Various embodiments provide an electrosurgical resector tool comprising: a shaft defining a lumen; an energy conveying structure for carrying electromagnetic (EM) energy through the lumen of the shaft; an instrument tip mounted at a distal end of the shaft. The instrument tip comprises: a static portion comprising a first blade element; and a movable portion comprising a second blade element, wherein the movable portion is movable relative to the static portion between a closed position in which the first blade element and second blade element lie alongside each other to an open position in which the second blade element is spaced from the first blade element by a gap for receiving biological tissue. The instrument tip also includes a travel limiting mechanism operable to limit a maximum extent of relative movement between the second blade element and the first blade element in the open position and/or the closed position. The instrument tip further includes a first electrode, a second electrode and a planar dielectric body, the first and second electrodes being spaced apart and electrically isolated from each other by the planar dielectric body, and wherein the first electrode and the second electrode are connected to the energy conveying structure for delivery of the EM energy from the instrument tip. The tool further comprises an actuator for controlling relative movement between the movable portion and the static portion.