A tissue ablation device, comprising: an array of bipolar electrodes configured to be coupled, in use, to an energy source wherein the array is configured to at least partially encircle a portion of an intended ablation that will at least partially encompass a target tissue and create an ablation pattern around a tissue volume including the target tissue, and configured to ablate the target tissue from an outside surface of the target tissue to an inner portion of the target tissue when the electrodes are energized, in use, by the energy source; characterised in that: the array of bipolar electrodes comprises bipolar electrodes that each separately deploy as a compound spiral electrode in a deployed state, each separately deployed electrode comprising a first portion (1403, 1406) and a second portion (1404, 1409), wherein the second portion (1404, 1409) is deployed through a lumen in the first portion (1403, 1406) and through an electrically insulative sleeve (1405, 1407) positioned between an interior wall of the lumen of the first portion and an exterior wall of the second portion; and in that: the first portion is energizeable to a first polarity and the second portion is energizeable to a second polarity that is different from the first polarity upon application of energy from the energy source. an array of bipolar electrodes configured to be coupled, in use, to an energy source wherein the array is configured to at least partially encircle a portion of an intended ablation that will at least partially encompass a target tissue and create an ablation pattern around a tissue volume including the target tissue, and configured to ablate the target tissue from an outside surface of the target tissue to an inner portion of the target tissue when the electrodes are energized, in use, by the energy source; characterised in that: the array of bipolar electrodes comprises bipolar electrodes that each separately deploy as a compound spiral electrode in a deployed state, each separately deployed electrode comprising a first portion (1403, 1406) and a second portion (1404, 1409), wherein the second portion (1404, 1409) is deployed through a lumen in the first portion (1403, 1406) and through an electrically insulative sleeve (1405, 1407) positioned between an interior wall of the lumen of the first portion and an exterior wall of the second portion; and in that: the first portion is energizeable to a first polarity and the second portion is energizeable to a second polarity that is different from the first polarity upon application of energy from the energy source. the array of bipolar electrodes comprises bipolar electrodes that each separately deploy as a compound spiral electrode in a deployed state, each separately deployed electrode comprising a first portion (1403, 1406) and a second portion (1404, 1409), wherein the second portion (1404, 1409) is deployed through a lumen in the first portion (1403, 1406) and through an electrically insulative sleeve (1405, 1407) positioned between an interior wall of the lumen of the first portion and an exterior wall of the second portion; and in that: the first portion is energizeable to a first polarity and the second portion is energizeable to a second polarity that is different from the first polarity upon application of energy from the energy source.