"A vision of Britain between 1801 and 2001. Including maps, statistical trends and historical descriptions." More focused on re-organising the data for access by locality than on enabling downloading of the raw data but have clearly put significant time and energy into data extraction. Specifically they have:
Listings of all reports published from 1801 to 1961,
and all tables in those reports.
Unless you ask, we list only reports and tables for which
we hold data or text.
The contents of selected tables, with headings and notes.
Introductory text [HTML_REMOVED] so far,
Abstracts 1801-41, Preliminary Reports 1851-1961,
and the 1911 General Report.
Openness: NOT OPEN
License: someone, somewhere holds copyright and there's no explicit license.
Access: all data is interwoven with text, graphics etc. Basically you'd need to do some really serious roboting/parsing to get any data out of this website, but most of the data can be obtained via the UK Data Archive at the University of Essex.