People leave religion all the time without any problem, but for many it is much more difficult. Regrettably, sometimes these people are called apostates, guilty of apostasy.
Atheism UK has compiled a list of organizations and information sources below. The following links may be helpful to anyone who has left, or is trying to leave religion:
Council of Ex-Muslims (CEMB)
DetentionAction: immigration detention centres support
ICORN – for writers and artists at risk
National Secular Society (NSS)
UK Apostasy and Asylum (CEMB)