This site has John Rocque's 1746 maps of London and the 1st Ordnance Survey 1863-80 map of London as well as historical data such as population figures.
http://www.locatinglondon.org
Poverty maps of London 1886-1903. PhoneBooth provides mobile access to the Charles Booth Maps, Descriptive of London Poverty 1898-9 and selected police notebooks which record eye-witness descriptions of London street-by-street. PhoneBooth is part of LSE Digital Library
The Index of Multiple Deprivation 2010 is provided by the UK Government Department of Communities and Local Government.
http://booth.lse.ac.uk
The National Library of Scotland has digitised over 20,000 maps at high resolution.
http://www.nls.uk/maps/index.html
A database of over 130,000 images from the London Metropolitan Archives and Guildhall Art Gallery.
http://collage.cityoflondon.gov.uk
Searchable 8 inch to a mile map of London from 1830.
http://www.motco.com/MAP/81003
Part of the British Library Online Gallery, this site has over 1200 digitised historical maps of London from 1570 to 1860.
http://www.bl.uk/onlinegallery/onlineex/crace/index.html
Free historical maps of Australia, London and some other parts of the UK. The site also includes some maps of Gallipoli.
http://archivemaps.com/mapco
Maps of London from the mid-twentieth century.
http://www.maps-of-london.com
