A terminal device for use in a wireless telecommunications network, the terminal device comprising: wireless communications receiver circuitry configured to receive signals from the infrastructure equipment via a wireless access interface provided by the infrastructure equipment, position detection receiver circuitry configured to receive a radio signal from which measurements can be used to assist in determining a position of the terminal device, and controller circuitry configured to control the wireless communications receiver circuitry to detect one or more system information blocks carrying position assistance information transmitted from the infrastructure equipment, the position assistance information providing information which can be used to assist in determining the position of terminal device, to control the position detection circuitry to estimate the position of the terminal device by combining the identified position assistance information with the radio signal received by the position detection receiver circuitry, wherein the controller circuitry is configured with the wireless communications receiver circuitry to receive from the infrastructure equipment an indication of relative risk that the position assistance information will change, and in response to the indication of the relative risk that the position assistance information will change to adapt the receiving of the one or more system information blocks to receive an updated version of the position assistance information in accordance with the relative risk, wherein the controller circuitry is configured in combination with the wireless communications receiver circuitry to detect the one or more system information blocks carrying the position assistance information in accordance with a discontinuous reception cycle comprising in a first part of the cycle for detecting the one or more system information blocks and a second part of the cycle in which the one or more system information blocks are not detected, and the controller circuitry is configured to adapt one or both of a length of the first and the second parts of the cycle in accordance with the relative risk. wireless communications receiver circuitry configured to receive signals from the infrastructure equipment via a wireless access interface provided by the infrastructure equipment, position detection receiver circuitry configured to receive a radio signal from which measurements can be used to assist in determining a position of the terminal device, and controller circuitry configured to control the wireless communications receiver circuitry to detect one or more system information blocks carrying position assistance information transmitted from the infrastructure equipment, the position assistance information providing information which can be used to assist in determining the position of terminal device, to control the position detection circuitry to estimate the position of the terminal device by combining the identified position assistance information with the radio signal received by the position detection receiver circuitry, wherein the controller circuitry is configured with the wireless communications receiver circuitry to receive from the infrastructure equipment an indication of relative risk that the position assistance information will change, and in response to the indication of the relative risk that the position assistance information will change to adapt the receiving of the one or more system information blocks to receive an updated version of the position assistance information in accordance with the relative risk, wherein the controller circuitry is configured in combination with the wireless communications receiver circuitry to detect the one or more system information blocks carrying the position assistance information in accordance with a discontinuous reception cycle comprising in a first part of the cycle for detecting the one or more system information blocks and a second part of the cycle in which the one or more system information blocks are not detected, and the controller circuitry is configured to adapt one or both of a length of the first and the second parts of the cycle in accordance with the relative risk.