1:625 000 Road Map
|Date range||1955 - 1956|
|Location||National Archives (see all files stored here)|
|File base||Series OS, subseries OS 1|
This file is that rarest of things - exactly what the description implies, and more. As well as both sheets of the 1956 Ten Mile Map of Britain, not flat but in good condition, it contains various draft copies of it as the OS tried experimenting with different colours, and a few notes on then recent changes (today's A1111 was created on 1st April 1956, for instance).
If you're been trawling through 6 rubbish files in quick succession, this little gem will make your day.
People with copies
Ritchie Swann has 300dpi scans of the main map itself, and the whole coverage is now available on SABRE Maps.