An electronic device comprises a touch screen and is configured to enter a lock state upon the fulfilment of a predetermined condition. The device is configured to display one or more images on the touch screen when the device is in the lock state, of which images one or more includes at least one predetermined point. The device is further configured to detect a touch on a predetermined point in one or more images and to deactivate the device lock state upon detection of a predetermined number of touches on successive images including a predetermined point.