Until recently, I was running my counselling business from a room in my rented flat (with the landlord's permission) and calculating a proportion of my rent and expenses as a business expense, as per HMRC guidance. I have had to move into my parents' home to help with care. As I see clients in person, I really need to keep my office where it is. Now that I do not live there and use the premises 100% for business, can I claim the whole of the rent as a business expense? I am mindful that as it is a domestic property, I pay council tax there, not business rates, so I wonder if this affects things. 

Arthur Weller replies:  

If you now use the flat 'wholly and exclusively' for business purposes, then as far as income tax is concerned, you can claim all the rent as a legitimate business expense. See HMRC’s Business Income Manual at BIM46801. The fact that you pay council tax there, and not business rates, is a separate matter.