Abstract The importance of a high standard of inspection and maintenance of offshore structures is evident from considerations of safety of personnel, prevention of loss of production due to shutdowns, or pollution of the sea due to oil discharges. These factors are highlighted by the occasional disaster, involving loss of life or the significant release of oil. Governments and certifying authorities have the responsibility for issuing and enforcing guidelines and regulations for inspection, but these obviously have to be based upon what is technically possible and, in many cases, the technology just does not exist to ensure the desired inspection standard. The commercial market for inspection in the North Sea alone is expected to grow to approaching £100 million by the mid-1980's, with a figure at least three times as high for the total world market.