The Philip Robinson Library has an extensive collection of Ordnance Survey and Geological Survey maps, located in ten map cabinets on Level 4. They are only available for use within the library.
Most of the maps held are flat, but the OS Landranger maps (Scale 1:50,000) are folded maps and are kept in metal drawers on top of the cabinet labelled Map Cabinet 8. Explorer Maps and Outdoor Leisure maps (Scale 1:25,000) are also held as folded maps and are kept in drawers on top of Map Cabinets 8 and 9.
Indexes to the maps are kept on top of the cabinets. Gazetteers and atlases are located on the shelves near the map cabinets.
More information here.