Awesome resource for you Sherlock Holmes book or Granada canon writers out there. The National Library of Scotland’s Map Department has taken some very high-resolution scans of the 1893 Ordnance Surveyset of 500+ maps of London and reorientated and stitched them together, so that they can be presented seamlessly on top of a “standard” Google web map or OpenStreetMap, with the base map acting as a modern context.
Read about it and then explore them here.