Abstract: An attachment system for detachably attaching an additional channel to an endoscope, the attachment system comprising: a sleeve for receiving a distal end of the endoscope and a distal end of the additional channel in use, the sleeve having: a sleeve body defining a sleeve channel, through which the distal end of the endoscope and the distal end of the additional channel will extend in use, and having a first open end and a second open end; a rupture mechanism for rupturing the sleeve body to allow separation of the distal end of the additional channel from the distal end of the endoscope.