It's less of a left - right thing (that's mainly economics). It paternalism Vs liberty thing. Labour have always had a very strong "we must protect the populace" theme to their policies. Conservatives have it too, but they want to do it in a different way.
Sadly it's a really difficult thing to stand against. Who wants to be labelled the person enabling paedophiles, when all you want is the right to private communication.