The present invention provides a breathing circuit 1 for delivering a flow of gases to a patient, the circuit comprising a connector 3 for connecting the circuit 1 to a patient. An inspiration tube 4 connected to the connector 3, the inspiration tube 4 being connectable to a ventilator 10 and for receiving an inflow of gases for the patient and an expiration portion 6. The expiration portion 6 comprises first and second expiratory tubes 7,8 connected to the connector 3. The first expiratory tube 7 is connectable to a ventilator 10, the first expiratory tube 7 in use providing a first expiratory flow path from the patient via the connector 3 and the first expiratory tube 7 to the ventilator 10. The second expiratory tube 8 is connected to an open-tail reservoir bag 9, the second expiratory tube 8 in use providing a second expiratory flow path from the patient via the connector 3 and the second expiratory tube 8 to the reservoir bag 9. The system further comprises a valve 5 operable to, in use, switch a flow of expiratory gases from the patient between the first and second expiratory flow paths 7.8. The system reduces storage space, material use and manufacturing costs whilst greatly enhancing convenience and safety for the patient.
