A detection apparatus and method arranged to detect defects within a flexible pipe at least partially surrounded by seawater. The detection apparatus comprises a seawater electrode, an impedance monitor and a processor. The seawater electrode is arranged to be in contact with seawater surrounding at least part of a flexible pipe. The impedance monitor is arranged to measure the impedance between a metallic structural component of the flexible pipe extending at least partially along the length of the flexible pipe and the seawater electrode in response to an electrical test signal applied to the seawater electrode. The processor is arranged to determine the distance from the seawater electrode to a pipe defect electrically connecting the metallic structural component to seawater using the measured impedance.