Police in the UK continue to arrest people for online posts that are reported as threatening, harassing, or grossly offensive.
  Cases are commonly brought under communications and public order laws, including offenses tied to harassment, malicious communications, and hate incidents.

There's a lot I don't like about the UK (enough that I left the country), but these things are not "criticising the government".

Closest the UK got, in recent years, to people getting punished specifically for criticising the government was that Mock the Week got cancelled. But not, say, Have I Got News For You, which has spent its entire existence doing nothing but.