This links to a large resource of maps for UK towns, historical OS maps, http://maps.nls.uk/towns/#london
Some key dates in British history, (to 31/1/1901) http://fooddeserts.org/images/000GreatBrit.htm
and from 1/1/1902, http://fooddeserts.org/images/050GreatBrit.htm
The maps resource can be overlaid on modern maps, or aerila imagery, so you can see exactly what's changed. Hosted by the National Libary of Scotland.
Dr Hillary J. Shaw
Director and Senior Research Consultant
Shaw Food Solutions
Newport
Shropshire
TF10 8QE
www.fooddeserts.org