Seismic safety considerations are required in the UK for those industries where the risk of failure is unacceptable. In the 1980s a series of studies were performed by Principia Mechanica Ltd (PML) that developed attenuation equations for PGA and spectral ordinates, suitable for use in the UK, which have since been widely used in hazard assessments. The increase in the numbers of strong-motion records and the major advances in strong-motion modelling, made it appropriate for the PML relations to be reviewed and, if necessary, updated. This paper presents an overview of a study carried out for this purpose. The study began by re-evaluating the PML equations repeating the regression analyses using re-calculated magnitudes and distances and alternative functional forms. These were found to produce minor, but not insignificant, differences in the predicted ground motions. The second stage of the work was to perform regression analyses on a new database of accelerograms from the SCRs, mainly from eastern North America (ENA). The large scatter in the equations was shown to be in part due to important regional differences between ENA, Europe and Australia, which were also identified by comparison of isoseismal patterns. Preliminary applications using the stochastic approach were then explored as an alternative, from which it was found that considerable additional work is needed to constrain input parameters, particularly site conditions at UK seismic stations and crustal structure in the region.