A content server delivers content items on demand to communications devices, and includes: a network interface configured to receive a content request from each of the communications devices and, in response to the received content requests, to transmit the content item to each of the communications devices following the arrival of a predetermined time using a network and one of a plurality of wireless access interfaces, each of the wireless access interfaces being configured to transmit and/or receive signals using a different radio access technology; and a control unit configured to cause the content transmitter to select one of the wireless access interfaces for transmitting the content item based on the number of content requests received prior to the arrival of the predetermined time; wherein the network interface is configured to transmit a signaling message to each of the communications devices signaling the selected wireless access interface prior to transmitting the content item.