Why the Church must be involved in politics

There seems to be an increasingly vocal minority of what can only be termed secular fundamentalists in the UK who want the Church and other faiths to stay out of politics because they disagree with parts of its agenda.  By politics I mean having an influence on policy and being involved in providing services.

Such thinking is not only deeply illiberal (ironic when many of the most passionate advocates of this cause claim strong liberal credentials), it goes against the interests of the poorest and most vulnerable people in the world.