I hold Bsc (applied biology),PGD Medical Microbiology,Msc Medical Microbiology,And Medical Labaratory Sciences (with specialist in Parasitology IMLS of Nigeria).
I would like to continue my studies in Water and Environmental Microbiology in the UK.
I am Nigerian but married to a British Citizen.

hi gloogbuagu,
i think you will find that being married to a British citizen will provide you with certain advantages. You might be eligible for home fees and for Research Council funding. It is however not the citizenship alone that will get you this, but the place of residency is important, too.
apart from that, you will have to find out how far your previous degrees are accepted at UK universities.
good luck!