http://labs.nationalarchives.gov.uk/wordpress/index.php/2010/03/uk-history-photo-finder
This tool allows you to search and view digitised historical photographs of the UK and Ireland. Starting with the Dixon-Scott collection, which holds more than 14,000 photographs taken in the 1920s-1940s, we will be adding new photographic resources in time. You can search by location and view images for free.