A gas and liquid supply system for an endoscope comprises a first gas flow channel having a first end configured for connection to a gas supply source and a second end arranged to supply gas to the distal tip of an endoscope. A second gas flow channel is provided having a first end in fluid connection with and extending from the first gas flow channel between the first and second ends of the first gas flow channel and an opposing distal end. A liquid supply channel is also provided. A connector is arranged for connecting the first end of the liquid flow channel to a liquid source. The connector comprises a first connection port configured for connection to an end of the liquid supply channel, and a liquid source connection channel in fluid connection with the first port for connecting the first port to a liquid supply. A second connection port is arranged for connection to the distal end of the second gas flow channel. The first port and the liquid source connection channel are fluidly isolated from the second port to prevent fluid communication between the second port and the liquid source.
