Hi.Being a company director is not classed as being self-employed I'm afraid and your business status dictates what you can claim.I cannot tell you why the law around such expenses is as it as and does not appear to make sense in some respects, particularly to a lay person, as I didn't write it or nor did I go through the thought processes which led to it. It is what it is and I've learned to accept it.Take a look at the notes starting at BIM47800 here and read right through to BIM47825 by clicking on "Next Page " at the bottom right of each web page. These pages tell you what you can claim and under what circumstances if you are self-employed. The expenses employees and as far as I am concerned directors can claim are set out starting at EIM32760 here and ending at EIM32790 where there are some examples.Employees and directors cannot generally claim tax reliefs for many expenses that the self-employed can. For an expense to be allowable for an employee or director, it has to be incurred "wholly, exclusively and necessarily" in the performance of their duties (EIM31630). You cannot claim that part of your house mortgage interest is incurred "wholly, exclusively and necessarily" for business purposes. For a self-employed individual, the term is "wholly and exclusively for business purposes". I realise this may seem like splitting hairs but that's the way it's been for pretty much all my 35 years in tax.If you look at BIM47820 here, you will see that where a room is used for part of a day to the exclusion of all other activities during the tiem it is being used for business purposes, you can claim for more than simply a proportion of the heating and lighting costs against your self-employed earnings including mortgage interest and council tax. Any claim you make has to have a logical basis. HMRC may ask for significant claims to be backed up with a logical explanation.I hope this helps but let me know if you have any further questions.