OPSI said the new Ordnance Survey data licensing terms have been conformed to the data.gov.uk licence terms, but ironically it's not possible to view the detailed OS terms at the time of writing, because the Ordnance Survey terms linked to by OPSI requires a login to access.
So, not very open yet, then. Hopefully they'll fix it soon. (That's no joke I promise you, you can trust me - just check my brain scan!)
UPDATE - see BBC news on free access to Ordnance Survey data and maps.
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