It can be simple to recognise maps where OS owns the copyright from the footnotes that are printed on all OS paper maps, for example: 'Made and published by Ordnance Survey, Southampton' and '© Crown copyright 2011' or from the OS copyright and database acknowledgement which should appear on all hard copy maps produced within HCC.
Because OS retain intellectual property rights (IPR) in maps and data derived from their copyright material almost all GIS data used by HCC includes OS IPR and is © Crown copyright.
Some digital material is easily recognised since it is very similar to the printed versions, but with some data it is not so obvious. You can confirm the IPR (lineage) and copyright by checking the metadata. For example, our GIS data for Minerals Resource Blocks (safeguarded mineral bearing land) has joint OS and HCC copyright. HCC copyright exists because it was made by us and Crown copyright because we traced features from the OS 1:10,000 map to make it.
The National Grid itself is the intellectual property of OS and therefore even data containing National Grid References alone is protected by Crown copyright if the point coordinates were derived from OS Licensed Data; if the point coordinates were captured using GPS however there would be no OS IPR and no Crown copyright.
Wherever OS material is reproduced you are reminded that it is a legal requirement that the appropriate OS copyright acknowledgement is displayed.