Last year he livestreamed[1] inside an English court and called the defendents - before they'd been convicted - muslim child rapists. He was attempting to intimidate witnesses. He threatened violence to the defendents and to some witnesses. He was told to stop. He did not stop.
That action put the trial at risk of collapsing.
He was caught, and given a suspended prison sentence for contempt of court. That judgement is available here: https://www.judiciary.gov.uk/publications/committal-for-cont...
Here's the judges words:
> The sentence, therefore, that I pass upon you, taking into account all of those matters that have been placed before me and your admissions entered via Mr. Kovalevsky, is one of three months' imprisonment which will be suspended for a period of 18 months. That will be suspended. There will be no conditions that need to be attached to that suspended sentence, but
you should be under no illusions that if you commit any further offence of any kind, and that would include, I would have thought a further contempt of court by similar actions, then that sentence of three months would be activated, and that would be on top of anything else that you were given by any other court.
> In short, Mr. Yaxley-Lennon, turn up at another court, refer to people as "Muslim paedophiles, Muslim rapists" and so on and so forth while trials are ongoing and before there has been a finding by a jury that that is what they are, and you will find yourself inside. Do you understand? Thank you very much.
What did he do after beign given this very clear instruction to not interfere with criminal trials? He did exactly the same thing again, and so his suspended sentence was activated, on top of the new sentence.
Note that he only highlights trials of child sexual abuse involving muslims. He kept very quiet when a senior EDL member was similarly prosecuted.
Here's a decent write up: https://thesecretbarrister.com/2018/05/25/what-has-happened-...
Interfering with ongoing trials and making threats of violence is as far from hought crime as you can get.
[1] There's been an element of "this would never happen in the US", so here's a video of someone being tased because they try to take a camera into court. https://youtu.be/A7U5eJN3hLI?t=2m0s