D is the person who is causing or allowing the nuisance.
• D cannot have to have an interest in the land e.g. a member of the owner’s family.
• This could be a local authority as in Tetley v Chitty.
• The occupier can still be liable even if they did not create the nuisance but they fail to deal with it. This could be something that a trespasser or the previous owner did as in Sedleigh Denfield v O’Callaghan.
• The nuisance could even be from natural causes: