An apparatus (200) for use in a telecommunications system. The apparatus (200) comprising a memory (240) and a controller (210). The controller (210) is configured to receive a radio frequency bandwidth and identify a first candidate carrier frequency (710) from the received a radio frequency bandwidth. The controller is further configured to, for a first potential radio access technology determine a probability estimate (Prob) for the first candidate carrier frequency (710) being a carrier frequency of the first potential radio access technology, where in the probability estimate is based on a received power in a transmission band of the first potential radio access technology having the candidate carrier frequency (710) and on a received power in a guard band of the first potential radio access technology having the candidate carrier frequency and from this select a radio access technology based on the probability estimate (Prob) for the candidate carrier frequency (710).