A flow control valve for a liquid conduit, such as a fire hydrant valve for insertion in a fire hydrant conduit, comprises a fixed valve body mountable inside the liquid conduit, a displaceable valve body, and an actuator assembly operatively engageable with the displaceable valve body. The fixed valve body has a peripheral wall and defines a longitudinal passageway, and at least one upstream port and a downstream port. The displaceable valve body is inserted into the longitudinal passageway of the fixed valve body and is linearly displaceable therealong between a closed configuration and at least one open configuration. The actuator assembly is operable to linearly displace the displaceable valve body along the longitudinal passageway of the fixed valve body between the closed configuration and the at least one open configuration.