Current records of Last Interglacial sea level are largely restricted to coral-based archives from low latitudes, where the sea-level record is both varied and contested, with multi-meter uncertainties, implying a range of scenarios from repeated phases of abrupt ice-sheet instabilities to models of more gradual ice-sheet melt. However, there are no reconstructions of Last Interglacial sea-level change from temperate latitudes that overlap in timing with low-latitude records and these records are needed in order to test for global synchronicity in these apparent jumps in sea level. Temperate, estuarine-type settings offer significant advantages over coral records, such as the potential for decimetre precision. Further refinements are possible with the application of microfossil-based analysis due to their prevalence in a range of environments and narrow ecological tolerances, which means they act as precise environmental indicators. By applying well-developed methodological approaches used in the reconstruction of Holocene sea-level records, to coastal sediments from northwest Europe deposited during late Quaternary interglacials, it may be possible to identify and quantify periods of rapid sea-level rise which may indicate ice-sheet instability. This is of critical importance for more accurate climate models and planning for future sea-level rise.