The present invention relates to a UMTS (Universal Mobile Telephone System) type system of mobile radio telecommunications that is robust with respect to radio network controller failures: According to the invention, following a temporary interruption in operation of a radio network controller of the UTRAN network of the system and after the reinitialization of this radio network controller, the UTRAN network sends a piece of information to all the cells controlled by the reinitialized radio network controller or by its neighboring radio network controllers. This piece of information prompts the user equipment devices that are in these cells to make their presence known to the UTRAN network. According to the invention, the user equipment devices in connected mode are capable of processing said piece of information.