... because Britain is a civilized nation that doesn't condone excessive violence, maybe? And a Communist uprising at this point would likely be completely quelled, as the Communists do not have the numbers for such a movement. Yet. So the leadership denounce the violence and bide their time for another, better opportunity.
NATO dogs cannot quell the revolutionary hearts and minds of the entire working class! We shall hunt down every Capitalist pig, NATO-supporting Coward, and Monarchist dog till the waters of Britain run with blood! We will follow our Jacobin comrades of the French Revolution! Off with their heads!