This invention relates to a coupling comprising a male part and a female part (7, 9), each having a ducting system (39) for the transmission of fluid (F) during the use of the coupling (1, 1′, 2), at least a front portion (13) comprising a main valve member (19) designed to prevent the fluid (F) from leaving the ducting system (39) when the coupling (1, 1′, 2) is uncoupled. An operating member (5) is connected to a pilot valve member (41, 63, 63″, 64) for controlling the flow of fluid (F) to and for pressurizing a valve chamber (45, 45″) in which a pressure relief valve member (33, 33′, 35, 35″) is designed to move into a position in which the ducting system (39) is opened or throttled.