An electrosurgical apparatus for coagulating tissue comprises an elongated tube (3) having a proximal end and a distal end, and constituting a conduit though which ionizable gas can be supplied to the distal end of the tube. The tube (3) includes one or more apertures (9) in the tube such that the ionizable gas is capable of exiting the tube in a plurality of different directions. The tube includes at least one electrode (4) for ionizing the ionizable gas exiting the one or more apertures, and a shield (11) associated to with the tube (3) and movable so as to obscure at least part of the one or more apertures (9) so as to vary the direction or directions in which the ionized gas exits the tube.