This is a state-of-the-art answer to a question that has come up in the past: how much of the Dictionary of National Biography on Wikisource is out of copyright in the UK?

I was prompted on this today, and realised we can now do the business properly (Petscan). See

https://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Dictionary_of_Natio...

Talking about the DNB first edition, which is US public domain, but applying the 70 year rule from death of author for UK copyright, a list of 32 authors results. That is around 5% of the 600-odd authors, but the affected proportion of articles will be noticeably less (complete listings are on the Wikisource author pages). There are usually caveats, and here there is a working assumption that we have a death date for the author. There will be a few more where Wikisource has failed to research such a date.

Charles