How can I sort my sbag landlord out!!?

Hi I am currently renting a property (privately) in Plymouth (UK) I paid my deposit in full and have never been in arrears. My problms began when the landlords shoddy plumbing resulted in a large scale flood, I reported this straight away to him and he sent out a plmuber who resolved the problem all fine up to this point he was then supposed to be renturning to deal with the water sodden flooring and sort out the damp woodwork, he left us with a wet (not damp just plain wet!) property for almost 6 months before pulling the floor up. But that is as far as he ever got so we are now left with severe rot in all the skirting boards and door frames (which are now black and crumbling) our shower no longer works as the plumbing is still crap. and we have been walking on the black sticky stuff that holds the flooring down for almost two months now! another problem is that all the flooring he pulled up he has left in the garden. He has prmised countless time to resolve these problems and has done nothing This is definately not safe for my 14 month old son who has had conjuctavitis on several occasions from the damp! My question is where do I stand on getting him to sort this mess out!! Iv been told by several people to refuse to give him his rent until he sorts the problem but I doubt that would work as iv been waiting over a week for him to collect his last lot of rent as he is such a useless lay about!!! We even went away for a week so that he could get the work done and he didnt even enter the proerty! Im literally furious that he expects us to live like this and am more than willing to take the s bag to court!!