The reduction is the basic rate value (currently 20%) of the lower of:
Finance costs: costs not deducted from rental income in the tax year (this will be a proportion of finance costs for the transitional years) plus any finance costs brought forward. Property business profits: profits of the property business in the tax year (after using any brought forward losses). Adjusted total income: income (after losses and reliefs, and excluding savings and dividends income) that exceeds your personal allowance.The tax reduction can’t be used to create a tax refund.If the basic rate tax reduction is calculated usingproperty business profitsoradjusted total income, then the difference between that figure andfinance costsis carried forward to calculate the basic rate tax reduction in the following years.
Accumulation or discretionary trusts enter residential finance costs in box 3.46. This amount will be used to calculate a reduction in income tax.For interest in possession trusts and estates of deceased persons, finance costs must not be entered in box 3.46. Instead, the finance costs are used by the beneficiaries as a basis for calculating their basic rate tax reductions. You’ll need to tell the beneficiaries the figures for the profits of each property business and the finance costs that relate to each business.