Thanks for all the replies. The person concerned does not have a paye income, and is self employed...some of his income does come from properties which are let out. As the property which is costing 10 grand a year in interest is part of his business ( it was not purchased for personal use ), does he really have to pay tax on the business turnover he uses to pay the interest on his business expense ie the business mortgage ? Its bad enough paying 10 grand in interest but having to earn say 16 grand or whatever to pay the interest is a different thing ...having to find say 6 grand extra in tax at the end of the year.