Prediction of Caesium-137 (Cs-137) deposition from atmospheric nuclear weapons tests. The methodology uses a ratio of Cs-137 deposition and precipitation measured at Milford Haven by the Atomic Energy Authority extrapolated across Great Britain using a 5 by 5 km resolution UKCIP precipitation dataset. The prediction is for 31 December 1985. Full details about this dataset can be found at https://doi.org/10.5285/c3e530bf-af20-43fc-8b4b-92682233ff08