The present invention relates to methods and arrangements for gathering statistics relating to random access operation in a cell of a cellular radio communication network and supervising such random access operation. Statistics are gathered (301), per random access preamble code, relating to random access detections associated with one or more random access preamble codes used in the cell. Based on such gathered statistics, random access operation in the cell may be supervised by evaluating (311) the gathered statistics and, upon determining (312) that the random access detections associated with a specific random access preamble code exhibit an abnormal behaviour likely to be caused by false random access preamble detections, initiating (313) at least one of issuing a corresponding operation and maintenance alarm signal and automatically blocking further use of said specific random access preamble code in the cell.