Legality around personal diary/journals.

[Circumferences]

Can anyone help me out here?

Out of curiosity is it illegal to read someone else's personal diary (from decades ago for context), I'm thinking "invasion of privacy" laws but they seem very unclear.
Are historical diaries legally protected in any way?

It definitely wouldn't be a theft to be clear, because the person had permitted access to the space where the journals were kept, and they were not hidden away. (They were in fact left out to be collected by the author but not collected, bit more context).

Lastly, if there is evidence of wrongdoing contained in these diaries can they be used as evidence without the consent of the author?

Tia.

IANAL (just someone who can't sleep), but I can't imagine why a diary should have any special legal status, or be considered different to any other written note kept at home. Nobody has to write a diary; if they voluntarily commit their thoughts to paper and leave that paper where others can access it, they surely can't expect the law to get involved. Else the police would constantly be called out in nosy little sibling disputes 😂 Will be interested if any legal experts advise otherwise!

To be clear, is this in a domestic context? Or did the person access the diary in some other capacity, e.g. in the workplace?

I suppose it depends what subsequently happens to the contents of the diary. Someone may have permission to physically take possession of the notebooks, but do they have permission to publish or otherwise disseminate? There could be copyright and privacy issues.

What’s the deal? Have they been given for private or public use?

What country are you in?

And when you ask about using them as evidence - in what context? Criminal prosecution?

All people involved are in the UK and it's a domestic/household setting.
It would be a criminal wrongdoing we're talking about yes, but written about from a Witness perspective.

Is it a safeguarding issue?

No it's not