"just how much like Thatcher is Cameron? ... how far is he prepared to go to crush dissent?"

Well this will be the interesting thing. How many pressure groups and charities will decide to stand together in opposition? 'Northern agitators' and 'dirty hippies' were very easily othered, but a broad coalition of support from people from all walks of life will be harder to ridicule and condemn. And if dissent is crushed (a la Thatcher) the govt. needs the propaganda machine of the press to succeed in othering dissenting groups, in order not to risk casting itself as a tyranny opposed to 'the people'.