An electrosurgical system includes a generator for generating radio frequency power, an electrosurgical instrument including at least first and second electrodes carried on the instrument, and a monopolar patient return electrode separate from the instrument. The generator comprises at least one source of radio frequency (RF) power, and has a first supply state in which the RF waveform is supplied between the first electrode and the patient return electrode, and a second supply state in which the RF waveform is supplied between a second electrode and the monopolar patient return electrode. A controller is operable to control the generator such that, in at least one mode of the generator, feeding means within the generator is adapted to alternate between the first and second supply states.