Digitising historical sea level records in the Thames Estuary, UK

London is one of the world’s most important coastal cities and is located around the Thames Estuary, United Kingdom (UK). Quantifying changes in sea levels in the Thames Estuary over the 20(th) century and early part of the 21(st) century is vital to inform future management of flood risk in London. However, there are currently relatively few long, digital records of sea level available in the Thames. Here we present a new extensive sea level dataset that we have digitised from historical hand-written tabulated ledgers of high and low water, from the Port of London Authority (PLA). We captured 463 years of data, from across 15 tide gauge sites, for the period 1911 to 1995. When these historical datasets are combined with digital records available from the PLA since 1995, the sea level time-series span the 111-year period from 1911 to 2021. This new dataset will be of great importance for ongoing monitoring of mean sea-level rise, and changes in tidal range and extreme sea levels in the Thames Estuary.