The invention discloses a method for detecting and controlling traffic congestion in a wireless telecommunications system (100, 300, 400) comprising at least a first node (130, 330, 430) such as a Radio Base Station, and at least one second node (110, 310, 410) such as a Radio Network Controller, the system also comprising a Transport Network, TN (120, 320, 420), for conveying traffic between said first and second nodes, in which system (100, 300, 400) the traffic can comprise one or more flow. The method comprises the use of one flow control function (315, 415) per each of said flows, said one flow control function (315, 415) comprising a congestion detection and control function. In addition, the congestion detection function acts to reduce the traffic on said flow before the system becomes congested.