A method and apparatus are described for controlling transmission of user data between a user equipment and a packet data via a packet switched data network, such as an Evolved Packet System (EPS). An association is formed between the user equipment and one or more gateways in the packet switched data network. In some embodiments, one or more messages are sent to the user equipment indicating a capability of the one or more gateways to inhibit transmission of user data towards the user equipment; an indication is received from the user equipment to inhibit transmission of user data to the user equipment from the first gateway, and, in response, transmission of user data towards the user from at least one of the gateways is inhibited. In some embodiments, in response to receipt of an indication from the user equipment to inhibit transmission of data towards the user equipment, a message is sent to the user equipment indicating parameters defining transmission characteristics of user data that may be transmitted between at least one of the gateways and the user equipment, and the gateways control transmission of data towards the user equipment in accordance with the sent parameters. This enables transmission of user data between a user equipment and a packet data network to be controlled.