I haven't yet been to the UK National Archives (well, I haven't been to the UK at all yet ...) but I probably will at some point for the PhD, and I have ordered documents from them before. So it's more than a little disturbing to learn via Schneier on Security via Patahistory that forged documents have been found in the archives, which were used to support a claim that British intelligence murdered Heinrich Himmler in 1945. It's true that historians are routinely suspicious of their primary sources, but that doesn't usually extend to being suspicious of their being primary sources at all! At least the forgery was detected, and it's unlikely anyone would care enough about my areas of interest for this to be a big problem for me.
There's a terse note confirming this at the National Archives.
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