Interference detection involves detecting the interference component in the received signal if there is such a component, controlling a band reject filter according to the detected interference component to filter the received signal to suppress the interference component, and synchronizing the receiver to the received signal, wherein the step of detecting the interference component is started before synchronization is achieved. By starting the interference detection without waiting for synchronization to be achieved, rather than following the synchronization, then the interference detection is no longer dependent on the synchronization being achieved.