As a sole trader, reporting self-employed income on your tax return, you can include up to £500 of financing costs as tagged expenses.
These can include:
bank, overdraft and credit card charges
interest on bank and business loans
hire purchase interest
We use the cash-basis for accounting which enforces this £500 limit.
Please note, if you're a landlord looking to include financing costs on your tax return the rules are different, take a look here.