A control apparatus (1) is configured to automatically update a neighbour relation table (40, 131) of a source cell (10A). The control apparatus (1) is further configured to add, to the neighbour relation table (40, 131), a new entry (41) indicating a neighbour-cell relation from the source cell (10A) to another cell (10B) different from both the source cell (10A) and a target cell (10C) of a handover from the source cell (10A), in response to receiving a first message (S105) that is issued when a radio terminal (2) that has experienced a failure involving disconnection of a radio link connection in the source cell (10A) or in the target cell (10C) attempts to re-establish the radio link connection to the other cell (10B). This contributes to updating the neighbour-cell relations in response to detection of a handover failure.