[en] In the UK there is a programme of nuclear safety research jointly agreed between the industry and the regulator. This paper gives an overview of the issues in the area of structural integrity and the research programme addressing these issues. Structural integrity is only one aspect of a much larger research programme. Two of the UK designs (Magnox and Advanced Gas-cooled Reactors) of nuclear plant are specific to the UK. The oldest Magnox plants have now operated for over 40 years, which is towards the limits of knowledge of exposure effects. The design of the early plant restricts accessibility for in-service inspection. The research programme is addressing these issues with projects on improved assessment methodologies, materials ageing and confirmation of inspection capabilities The later advanced gas-cooled reactors (AGRs) have components which operate in the creep regime, and are accumulating longer periods of high temperature operation where irradiation, thermal ageing and environmental effects are becoming more evident. In addition to the primary objective of ensuring safe operation there is increasing pressure to maximise output and to increase availability. Validation of defect methodologies for high temperature components is important. The AGRs are constructed from a wide variety of materials, each with its own material specific ageing and degradation mechanisms also to consider. The research programme is addressing the above issues. (orig.)