Electrosurgical apparatus and method for promoting haemostasis in biological tissue

An electrosurgical apparatus (figure 1) configured to produce an electrosurgical waveform 500 having both radiofrequency (RF) energy and microwave energy components that is arranged to perform efficient haemostasis in biological tissue. The waveform comprises a first portion 506 primarily of RF electromagnetic energy 502, and a second portion 508 primarily of microwave electromagnetic energy 504 that follows the first portion 506. The second portion 508 further comprises a plurality of RF pulses 510, wherein the first portion 506 transitions to the second portion 508 when either a duration of the first portion meets or exceeds a predetermined duration threshold, or an impedance determined during the first portion meets or exceeds a predetermined threshold. The waveform is arranged to deliver energy rapidly so that haemostasis can occur in a short time frame in a situation where the maximum available power is limited, or to avoid undesirable thermal damage to the biological tissue. A method is also claimed.