A method performed by a management node (160, 180, 260, 360) in a cellular telecommunications network, the cellular telecommunications network including a first base station and a User Equipment, UE, wherein the first base station is configured to transmit a first tracking area code and the UE is configured to send a tracking area update request message to the first base station identifying the first tracking area code, the method comprising the steps of: receiving a request message from the first base station, the request including the first tracking area code identified in the tracking area update request message; the method characterised by: the management node (160, 180, 260, 360) storing a first set of tracking area codes, comparing the received first tracking area code to the first set of tracking area codes; and sending a response message to the first base station, the response message accepting or rejecting the tracking area update area request based on the comparison, wherein: each of the first set of tracking area codes is associated with a base station that supports a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes accepting the tracking area update request if the received tracking area code is one of the first set of tracking area codes, or each of the first set of tracking area codes is associated with a base station that does not support a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes rejecting the tracking area update request if the receiving tracking area code is one of the first set of tracking area codes. receiving a request message from the first base station, the request including the first tracking area code identified in the tracking area update request message; the method characterised by: the management node (160, 180, 260, 360) storing a first set of tracking area codes, comparing the received first tracking area code to the first set of tracking area codes; and sending a response message to the first base station, the response message accepting or rejecting the tracking area update area request based on the comparison, wherein: each of the first set of tracking area codes is associated with a base station that supports a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes accepting the tracking area update request if the received tracking area code is one of the first set of tracking area codes, or each of the first set of tracking area codes is associated with a base station that does not support a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes rejecting the tracking area update request if the receiving tracking area code is one of the first set of tracking area codes. the management node (160, 180, 260, 360) storing a first set of tracking area codes, comparing the received first tracking area code to the first set of tracking area codes; and sending a response message to the first base station, the response message accepting or rejecting the tracking area update area request based on the comparison, wherein: each of the first set of tracking area codes is associated with a base station that supports a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes accepting the tracking area update request if the received tracking area code is one of the first set of tracking area codes, or each of the first set of tracking area codes is associated with a base station that does not support a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes rejecting the tracking area update request if the receiving tracking area code is one of the first set of tracking area codes. each of the first set of tracking area codes is associated with a base station that supports a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes accepting the tracking area update request if the received tracking area code is one of the first set of tracking area codes, or each of the first set of tracking area codes is associated with a base station that does not support a circuit switched voice service, and the step of accepting or rejecting the tracking area update request includes rejecting the tracking area update request if the receiving tracking area code is one of the first set of tracking area codes.