Over the past five decades Cumbria has been subject to radiocaesium deposition from a number of sources. In the event of a future nuclear accident, estimates of baseline radiocaesium deposition in Cumbria would be indispensable. This paper describes the application of ordinary block kriging to estimate the spatial variation of total 137Cs and 134Cs. This study has raised a number of issues regarding the application of kriging. Transformation of input data was necessary to improve the optimality of the standard kriging estimator. Finally, observations of 137Cs and 134Cs from a similar range of locations exhibit different spatial characteristics. This can be explained by differences in radioactive half-lives and differences in the deposition of the two isotopes.