The National Library of Scotland was quick off the mark, putting online 9,851 maps at scales of 1:1,250 to 1:10,560 published in 1975. They came out-of-copyright on 1 January 2026.
These maps cover areas in England, Northern Ireland, Scotland and Wales, and include 2,872 more detailed maps at scales of 1:1,250, 6,281 maps at 1:2,500, and 699 less detailed maps at scales of 1:10,000/1:10,560 . A graphic index includes these new maps published in 1975. These are usually the most detailed, basic scales of Ordnance Survey maps for these areas.
Check here if you missed any recent additions.
Hard to believe that anything 10 years younger than me is now Out of Copyright! *sigh*
That said, very useful for more recent research 😊