One step at a time. Softly, softly does it.
You would hardly expect the majority of Muslims in the UK to demand complete sharia law here and now. That's not going to happen. Clowns such as Angie Choudary, of course, do demand complete Islamisation over night. (That's why I sometimes think he's either a Muslim plant or he works for the Government.)
What Angie Choudary should be doing - because it's far more effective - is the Islamisation-one-step-at-a-time approach of, say, the Muslims Council of Britain (MCB) and other Officially Moderate Muslim groups.
Many Muslims make the extremely bogus distinction between "civil sharia" and "state sharia" (i.e., stuff that would effect everyone). They say it's all about "little changes" to do with inheritance tax, marriage law, halal produce, Islamic bonds, etc. But what happens when Muslims gain all these "civil" concessions? Will they suddenly stop demanding more "religious" Sharia laws? Of course they won't!
The demands for "sharia finance" and changes in inheritance law are just the first steps towards complete Islamisation. And increased Islamisation will coincide with increased Muslim demographics. (This, again, makes the Angie Choudary approach seem a little suspect if not counterproductive, from a Muslim point of view).