Demonising opposition to the ruling party as being unpatriotic has a long history in fascist, communist and other authoritarian dictatorships.
Typically this involves the use of vitriolic terms of abuse, labelling reasonable concerns as extreme, as exemplified here.
Together with control of the media, suppression of rights to assemble and voting rights, these propaganda tactics, taken up enthusiastically by government supporters as seen here, also often characterise the slide into authoritarian government. Punishment of out groups such as religious or racial minorities in performative ways is also common. A charismatic leader will be ascribed special powers which allow him (it's always a him) and only him to save the country from the malaise brought on by these enemies from without, who are aided by the "enemies of the people" within, invariably including intellectuals and the like.
But at least the previous paragraph isn't descriptive of today's Britain. Is it?