Arresting a person for holding a blank placard would indeed be Russia-level oppression. The person in question was not arrested, but threatened to be arrested if he wrote a particular phrase on it [1]. Not great at all, but still no cigar.

A man wearing the "Plasticine Action" T-shirt was indeed arrested [2]. That was extra absurd because the protest was against AI-generated animation, not about a political cause.

All in all, quite bad :(

[1]: https://www.standard.co.uk/news/uk/police-arrest-blank-paper...

[2]: https://www.independent.co.uk/news/uk/crime/palestine-action...