I borrowed £15,000 from my credit card company as the deposit for a £100,000 flat, and also borrowed £85,000 from the buy-to-let company.  I know that the interest on the £85,000 buy-to-let loan is tax deductible. The £15,000 has zero interest for 12 months so I will not be charged any interest until month 13. My main question: Is the interest from the 13th month of the credit card loan of £15,000 tax deductible in the same way as the interest from the £85,000 loan from the buy-to-let company? Is the interest tax deductible until the capital of the original £15,000 from the credit card company is completely paid off?

The answer to the question is that the credit card interest is allowable. See HMRC’s Property Income manual at PIM2105 (www.hmrc.gov.uk/manuals/pimmanual/PIM2105.htm), where you can see that the crucial point is what is the borrowed money used for. If it is used wholly and exclusively to fund the business and/or purchase of the business asset then even overdraft interest is allowable and even when the security for the loan is the taxpayer’s own residence; see

BIM45685 (www.hmrc.gov.uk/manuals/bimmanual/BIM45685.htm).