The London Basin 1:50 000 resolution geological model covers a total area of 4 800 km2 in southeast England (Figure 1), stretching from easting 450 000 to 570 000 and from northing 160 000 to 200 000. Because of the large size of the modelled area, the initial construction was divided into twelve 20 x 20 km tiles (Figure 1). A separate 3D geological model was constructed for each tile using the GSI3D software and methodology (Kessler & Mathers 2004, Kessler et al. 2009). The twelve model tiles were later merged into a unified model and subsequent modelling and calculation of the bedrock units was completed in GOCAD®. This report summarises the metadata compiled during the construction of the individual tiles and the development of the combined model.