Lewis's Topographical Dictionary
This is another edition of this map, drawn by Creighton and engraved by T Starling, this time featuring Poor Law Union boundaries (and proposed railways from London - past Colchester into Suffolk, past Saffron Walden into Cambridgeshire, and the never built cross-county line to Thameshaven).
Scale correct at 15 miles = 52.5mm, or 7.25 miles/inch, ie 1:455,000.
The Dictionary first appeared in 1831, then in 1833, 35, 38, 40, 42, 45 and 49, often with further information added/removed.