An electrosurgical device that is capable of both generating a plasma to perform surface coagulation and emitting a non-ionising microwave field (in the absence of plasma) to perform coagulation at a deeper level. The device comprises a probe tip that is connected to receive radiofrequency (RF) and/or microwave frequency energy from a generator, and also defines a flow path for a gas. The probe tip is adjustable between a first configuration, in which it defines a bipolar (e.g. coaxial) structure to produce a high electric field from the received RF and/or microwave frequency energy across the flow path for the gas to strike and sustain plasma and a second configuration, in which it defines an antenna structure to emit non-ionising microwave energy into tissue.
