Project summary: Detecting accelerations in the rate of sea-level rise is not straightforward. However, these forecasts are important for long-term planning for coastal infrastructure and are vital for informing adaptive planning. The aim of this project was to better understand likely lead times for upgrading/replacing coastal defence infrastructure around the UK coast and to assess whether we could detect sea-level accelerations earlier to provide sufficient lead time for action. We developed an active academic and stakeholder group to discuss the issues, challenges and implications relating to detection of sea-level accelerations and the lead times required to upgrade/replace different types of coastal defence infrastructure. We calculated rates of sea level acceleration around the UK, before and after accounting for inter-annual variability. We showed that while sea-level rise is accelerating, we have high confidence it is below the thresholds currently used for management of the Thames Estuary 2100 plan.Finally, we explored the feasibility of combining in situ and satellite-based data with statistical models to develop a toolbox which will help identify timings of future sea-level rise rates and, accordingly, to estimate lead times. This tool will help the Environment Agency to better plan for the future and implement more effective adaptive management pathways.