A cable (1, 17, 31, 39, 47, 55, 59, 63) for conveying radiofrequency and/or microwave frequency energy to an electrosurgical instrument at a first end of the cable, the electrosurgical instrument comprising a first cooperating terminal and a second cooperating terminal; the cable comprising: a hollow tube comprising inner (5, 19, 33, 43, 49, 119, 133) and outer (23, 37, 45, 53, 9, 123, 137) electrically conductive layers separated by dielectric material (7, 21, 35, 41, 51, 121, 135) to form a transmission line, the hollow tube having a central channel extending along its length; characterised in that the cable further comprises: a first terminal at the first end of the cable, the first terminal being arranged to form a releasable electrical connection between the inner conductive layer and the first cooperating terminal of the electrosurgical instrument; and a second terminal at the first end of the cable, the second terminal being arranged to form a releasable electrical connection between the outer conductive layer and the second cooperating terminal of the electrosurgical instrument, wherein the first terminal comprises a first electrically conductive protrusion (125a, 147a) extending in an axial direction from the first end of the cable and electrically connected to the inner conductive layer (5, 19, 33, 43, 49, 95, 119, 133); and/or wherein the second terminal comprises a second electrically conductive protrusion (125b, 147b) extending in an axial direction from the first end of the cable and electrically connected to the outer conductive layer (23, 37, 45, 53, 9, 103, 123, 137); and wherein a releasable bipolar electrical connection between the cable (1, 17, 31, 39, 47, 55, 59, 63) and the electrosurgical instrument is formed by electrically connecting the first terminal to the first cooperating terminal and electrically connecting the second terminal to the second cooperating terminal. a hollow tube comprising inner (5, 19, 33, 43, 49, 119, 133) and outer (23, 37, 45, 53, 9, 123, 137) electrically conductive layers separated by dielectric material (7, 21, 35, 41, 51, 121, 135) to form a transmission line, the hollow tube having a central channel extending along its length; characterised in that the cable further comprises: a first terminal at the first end of the cable, the first terminal being arranged to form a releasable electrical connection between the inner conductive layer and the first cooperating terminal of the electrosurgical instrument; and a second terminal at the first end of the cable, the second terminal being arranged to form a releasable electrical connection between the outer conductive layer and the second cooperating terminal of the electrosurgical instrument, wherein the first terminal comprises a first electrically conductive protrusion (125a, 147a) extending in an axial direction from the first end of the cable and electrically connected to the inner conductive layer (5, 19, 33, 43, 49, 95, 119, 133); and/or wherein the second terminal comprises a second electrically conductive protrusion (125b, 147b) extending in an axial direction from the first end of the cable and electrically connected to the outer conductive layer (23, 37, 45, 53, 9, 103, 123, 137); and wherein a releasable bipolar electrical connection between the cable (1, 17, 31, 39, 47, 55, 59, 63) and the electrosurgical instrument is formed by electrically connecting the first terminal to the first cooperating terminal and electrically connecting the second terminal to the second cooperating terminal. a first terminal at the first end of the cable, the first terminal being arranged to form a releasable electrical connection between the inner conductive layer and the first cooperating terminal of the electrosurgical instrument; and a second terminal at the first end of the cable, the second terminal being arranged to form a releasable electrical connection between the outer conductive layer and the second cooperating terminal of the electrosurgical instrument, wherein the first terminal comprises a first electrically conductive protrusion (125a, 147a) extending in an axial direction from the first end of the cable and electrically connected to the inner conductive layer (5, 19, 33, 43, 49, 95, 119, 133); and/or wherein the second terminal comprises a second electrically conductive protrusion (125b, 147b) extending in an axial direction from the first end of the cable and electrically connected to the outer conductive layer (23, 37, 45, 53, 9, 103, 123, 137); and wherein a releasable bipolar electrical connection between the cable (1, 17, 31, 39, 47, 55, 59, 63) and the electrosurgical instrument is formed by electrically connecting the first terminal to the first cooperating terminal and electrically connecting the second terminal to the second cooperating terminal.