This disclosure provides a method, and a network node for implementing the method, of switching a base station in a cellular telecommunications network between a first and second mode, in which the base station uses more energy when operating in the first mode than the second mode, wherein the cellular telecommunications network further includes a User Equipment, UE, having a camera, the method including storing visual data including a visual representation of at least a part of the base station; receiving visual data captured by the camera of the UE; performing a computer vision operation, trained on the stored visual data, on the captured visual data to determine whether the visual representation of the base station or part thereof is present in the captured visual data; and, in response initiating a switch in the base station between the first and second modes.