Can you an example of a person who was convicted and exactly what they said?
If police question you based on your speech alone, that itself is a violation. You should not have to answer to the state for voicing disagreement or for having an unpopular opinion.
Here's an example of half a dozen police officers coming to talk to parents for complaining about their school in a private WhatsApp group: https://www.theguardian.com/uk-news/2025/mar/29/parents-arre... (they were later arrested)
Here's a police officer saying on video that if you tell someone to speak English it "could be perceived as a hate crime:" https://x.com/PeterSweden7/status/1911348268346323047
This was a partially deaf person asking the person they were talking to to please speak clearly (no mention of language was made, not that it should matter). The only appropriate response to a police officer coming up to you to discuss the interaction is profanity.
Here's multiple arrests for protests after the death of the Queen: https://www.bbc.com/news/uk-62883713
These are ones I found with a Google search in under ten minutes. I'm sure there are dozens, hundreds more - one link I didn't open said there have been approximately 3,000 arrests based on social media posts. I'm sure some of those are justified, I'm sure a lot of them aren't.
A conviction does not need to happen for damage to be done or for speech to be chilled.