Comment by dmix

In the UK the police can detain you for up to 24hrs without a judge and extend it to 36hrs in some cases.

One case I read of a guy who got in trouble for a social media post, he was called into the station and they basically forced him to sign a paper otherwise he couldn't leave as they'd just keep interrogating him, where I'd imagine they threatened to get the courts involved unless he admitted he was wrong for doing it. Which is why most of them don't end up as convictions.

It's basically a very aggressive warning.

Example: https://www.aol.com/police-apologise-arresting-former-specia...

> Mr Foulkes was detained in a police cell for eight hours and questioned in relation to a potential charge of malicious communications. He said he ended up accepting an unconditional caution because he feared the investigation could affect his visits to his daughter in Australia.

Another https://www.foxnews.com/world/blogger-arrested-sharing-anti-...

> After being questioned for several hours, North was released without charge.