Black Mould - Can council rehouse ?

Talk to your landlady again tell her that the problem needs to be addressed due to health reasons. If the do not do anything go to your local housing authority and talk to them. It is against the law for them not to come in and fix the problem have it tested and cleaned up. Most likely there is a leak of some kind somewhere. Scream Unfair housing to your local housing authority if they don't do anything to help. That will get your landlady on the ball