Sterilization apparatus comprising a sterilization instrument configured to be inserted through the instrument channel of a surgical scoping device and a withdrawal device for withdrawing the sterilization instrument from the instrument channel at a predetermined rate. The sterilization instrument comprises an elongate probe having a probe tip with a first electrode and a second electrode arranged to produce an electric field from received RF and/or microwave frequency EM energy. In operation the instrument may disinfect an inner surface of the instrument channel by emitting energy while being withdrawn through the channel.
