Within the GSWP2 framework we assess the simulated hydrology of the standard U.K. Met Office land surface scheme (MOSES). A modified version (MOSES-LSH) which includes a topographically-based representation of sub-gridscale soil moisture, is also evaluated. Particular focus is given to the effect of the latter on systematic runoff biases in MOSES. Differences in the temporal variability of the two schemes is also assessed. Detailed analysis is carried out over regions which are highly sensitive to the parameterisation of soil moisture heterogeneity.