An electrosurgical instrument for applying radiofrequency energy and/or microwave frequency energy to biological tissue, the instrument comprising: a distal part comprising an instrument tip for applying radiofrequency energy and/or microwave frequency energy to biological tissue, wherein the instrument tip comprises a first conductive element and a second conductive element; a coaxial feed cable comprising an inner conductor, a tubular outer conductor coaxial with the inner conductor, and a dielectric material separating the inner and outer conductors, the coaxial feed cable being for conveying radiofrequency energy and/or microwave frequency energy to the distal part; wherein: the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element through a rotatable connection between the distal part and the coaxial feed cable that allows rotation of the distal part relative to the coaxial feed cable about a central axis of the distal part; the instrument comprises an actuator element for rotating the distal part relative to the coaxial feed cable; and the actuator element is configured to be moved axially along the instrument; characterized in that the distal part comprises a path on the instrument tip along which a part of the actuator element travels when the actuator element is moved axially, thereby causing the distal part to rotate. a distal part comprising an instrument tip for applying radiofrequency energy and/or microwave frequency energy to biological tissue, wherein the instrument tip comprises a first conductive element and a second conductive element; a coaxial feed cable comprising an inner conductor, a tubular outer conductor coaxial with the inner conductor, and a dielectric material separating the inner and outer conductors, the coaxial feed cable being for conveying radiofrequency energy and/or microwave frequency energy to the distal part; wherein: the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element through a rotatable connection between the distal part and the coaxial feed cable that allows rotation of the distal part relative to the coaxial feed cable about a central axis of the distal part; the instrument comprises an actuator element for rotating the distal part relative to the coaxial feed cable; and the actuator element is configured to be moved axially along the instrument; characterized in that the distal part comprises a path on the instrument tip along which a part of the actuator element travels when the actuator element is moved axially, thereby causing the distal part to rotate. the inner conductor is electrically connected to the first conductive element and the outer conductor is electrically connected to the second conductive element through a rotatable connection between the distal part and the coaxial feed cable that allows rotation of the distal part relative to the coaxial feed cable about a central axis of the distal part; the instrument comprises an actuator element for rotating the distal part relative to the coaxial feed cable; and the actuator element is configured to be moved axially along the instrument; characterized in that the distal part comprises a path on the instrument tip along which a part of the actuator element travels when the actuator element is moved axially, thereby causing the distal part to rotate.