Copyright does lapse on old maps, this is how libraries can sell copies of them. I suspect that the notice on the Old Maps website is because they have digitised the maps themselves. The following is from the OS website:
Ordnance Survey mapping is protected by the 1988 Copyright, Designs and Patents Act. Mapping is covered for 50 years from the end of the year in which the map was first published, for example, a map dated 1942 would have gone out of copyright on December 31 1992.
Pete Joseph
|