In a radio system the user terminal performs measurements of at least one pilot signal. The user terminal has a packet switched connection with a GSM cell. At least one of the at least one measured pilot signals is transmitted by a UTRAN cell. The user terminal transmits measurement reports including pieces of information of quality of the at least one pilot signal to a base station controller which compares the quality of the at least one pilot signal originating from a UTRAN cell with a predetermined threshold. The base station controller (106) selects a UTRAN cell as a target of an intersystem cell reselection if the quality of the pilot signal from the UTRAN cell maintains better than a predetermined threshold for a predetermined threshold period of time.