The present invention relates to a sensor for detecting the presence of a botulinum neurotoxin in a sample, the sensor comprising: (a) an electrically conductive substrate coated with at least one SNAP-25, VAMP or syntaxin protein; and (b) a detection arrangement adapted to enable the detection of the cleavage of at least one SNAP-25, VAMP or syntaxin protein by the botulinum neurotoxin. The invention also relates to methods of making a sensor, methods of detecting and a detection kit for botulinum neurotoxin.