An electrosurgical resector tool having an energy delivery structure that provides a plurality of operational modalities that facilitate biological tissue cutting and sealing using radiofrequency (RF) electromagnetic energy and/or microwave EM energy. The tool comprises a static first blade element, and a pivotable second blade element that has a length commensurate with the first blade element whereby, in a closed position, it lies adjacent to a laterally facing surface of the first blade element. The blade elements constitute an energy delivery mechanisms that is compact enough to enable the tool to be insertable through an instrument channel of a surgical scoping device, such as an endoscope, gastroscope or bronchoscope.