is my back door a fire exit, I live alone and have been told by my landlord that I am in breach because my back door is not clear.my back door has a screen door and two locks, this I find odd being a fire exit, please can you advise me.

You are talking about a domestic premises which is not subject to any regulations therefore you cannot be in breach of anything regarding the property, if it is a flat then the commons areas are subject to The Regulatory Reform (Fire Safety) Order 2005. Ask your landlord what legislation you are in breach of and for him to explain the relevant parts.