A method for use in a wireless telecommunications network, the mobile telecommunications network comprising a core network, two or more base stations (101 (eNB1, eNB2, eNB3)) each providing wireless connectivity within a base station cell, and a terminal device configured to communicate wirelessly with the base stations (101 (eNB1, eNB2, eNB3)) by a communication mode, the method being a positioning method for determining a position of the terminal device, and the method comprising: configuring the terminal device for operation in a transmission phase using a connected communication mode before the transmission phase, the transmission phase comprising sending positioning signals from the base stations (101 (eNB1, eNB2, eNB3)) to arrive at the terminal device for the terminal device to measure arrival times of the positioning signals, the method being an observed time difference of arrival method, sending one or more positioning signals between the base stations and the terminal device during the transmission phase of the method, transitioning the terminal device into an energy saving communication mode for the transmission phase in which the arrival time measurements of the positioning signals from the base stations (101 (eNB1, eNB2, eNB3)) are performed, transitioning the terminal device to a connected communication mode when the transmission phase ends for the purpose of reporting time differences in the measured arrival times from the terminal device to elsewhere in the network, and using the measured arrival times of the positioning signals to triangulate a position of the terminal device, wherein during the transmission phase the terminal device is in an energy saving communication mode comprising one of an idle communication mode or a suspended communication mode, and during the transmission phase there is no radio channel connection between the base station and the terminal. configuring the terminal device for operation in a transmission phase using a connected communication mode before the transmission phase, the transmission phase comprising sending positioning signals from the base stations (101 (eNB1, eNB2, eNB3)) to arrive at the terminal device for the terminal device to measure arrival times of the positioning signals, the method being an observed time difference of arrival method, sending one or more positioning signals between the base stations and the terminal device during the transmission phase of the method, transitioning the terminal device into an energy saving communication mode for the transmission phase in which the arrival time measurements of the positioning signals from the base stations (101 (eNB1, eNB2, eNB3)) are performed, transitioning the terminal device to a connected communication mode when the transmission phase ends for the purpose of reporting time differences in the measured arrival times from the terminal device to elsewhere in the network, and using the measured arrival times of the positioning signals to triangulate a position of the terminal device, wherein during the transmission phase the terminal device is in an energy saving communication mode comprising one of an idle communication mode or a suspended communication mode, and during the transmission phase there is no radio channel connection between the base station and the terminal.