The Shift from Deductions to Tax Credits
In the past, the UK tax system treated buy-to-let property as a business where mortgage interest was considered a standard operating expense. Landlords would subtract their mortgage interest from their gross rental income, and only the remaining profit was subject to Income Tax. This meant that if a landlord paid tax at the 40% or 45% rate, they effectively received relief at that same high rate.
Section 24 of the Finance (No. 2) Act 2015 changed this fundamental principle for individual landlords. Since the full implementation in April 2020, mortgage interest is no longer an allowable deduction from rental income for individuals. Instead, it has been replaced by a 20% tax credit. This change applies to all individual landlords of residential property, although it does not apply to owners of Furnished Holiday Lets (FHLs) or properties held within a limited company structure.
The Mathematical Reality of the 20% Credit
The transition from a deduction to a credit is not just a change in terminology; it is a change in how your taxable income is calculated. Under the current rules, you are taxed on your total rental income minus property expenses such as repairs, insurance, and management fees. Crucially, mortgage interest is not included in these expenses. Once your total tax liability is calculated based on your total income, you then apply a credit equal to 20% of your finance costs to reduce the final bill.
The impact of this depends entirely on your tax bracket. For a basic rate taxpayer, the effect is largely neutral because the 20% credit matches the 20% tax rate. However, for higher rate (40%) and additional rate (45%) taxpayers, the tax relief has effectively been halved or more. You are now paying tax on the full amount of the interest at your marginal rate, but only receiving a smaller partial offset back.
Defining Finance Costs
It is important to understand what HMRC considers a 'finance cost' for the purposes of this credit. It is not limited strictly to the interest portion of your monthly mortgage payment. It also includes:
- Interest on loans taken out to buy or improve the property.
- Interest on loans to purchase furnishings for the property.
- Incidental costs of obtaining finance, such as mortgage arrangement fees or valuation fees required by the lender.
- Fees paid to intermediaries or brokers for arranging the loan.
- Early repayment charges if you exit a mortgage deal early.
The Hidden Trap: Artificial Income Inflation
Perhaps the most significant pitfall of Section 24 is how it affects your total income figure. Because you can no longer deduct interest before declaring your profit, your 'taxable income' appears much higher on paper than it did previously. This 'artificial inflation' of income can have several unintended consequences even if you were previously a basic rate taxpayer.
Firstly, it can push a landlord whose total income was comfortably within the basic rate band (£12,571 to £50,270) into the higher rate band. Because the 20% credit is applied after the tax rate is determined, a landlord could find themselves paying 40% tax on a portion of their income but only receiving 20% relief on their interest, creating a significantly higher tax bill.
Secondly, this higher total income figure could result in the loss of certain state benefits. For example, if a landlord's total income rises above £50,000, they may become liable for the High Income Child Benefit Charge. If total income rises above £100,000, the personal allowance begins to taper away at a rate of £1 for every £2 earned, leading to an effective tax rate of 60% in that specific income bracket.
Practical Scenarios
To see how this works in practice, consider a landlord with £15,000 in rental income and £8,000 in mortgage interest. We will assume they have a separate salary that already uses up their personal allowance.
Scenario A: The Higher Rate Taxpayer
If the landlord is a 40% taxpayer, they are now taxed on the full £15,000. The tax at 40% is £6,000. They then receive a credit of 20% on their £8,000 interest, which is £1,600. The final tax bill is £4,400 (£6,000 minus £1,600). Under the old system, they would have only paid tax on the £7,000 profit (£15,000 minus £8,000), resulting in a tax bill of £2,800. Their tax has increased by £1,600 despite their actual cash profit remaining the same.
Scenario B: The 'Pushed' Taxpayer
Consider a landlord with a salary of £45,000 and a net rental profit (after other expenses but before interest) of £10,000. They have £6,000 in mortgage interest. Previously, their total taxable income would have been £49,000 (£45,000 plus £4,000 profit), keeping them a basic rate taxpayer. Now, their taxable income is £55,000 (£45,000 plus £10,000). They have been pushed into the higher rate band for £4,730 of their income, even though their actual cash position has not improved.
The Shift to Limited Companies
Because Section 24 specifically targets individuals, many landlords have explored moving their properties into a limited company. Companies are not subject to Section 24; they can still deduct 100% of mortgage interest as a business expense before paying Corporation Tax on the remaining profit. This can be more tax-efficient for those who fall into the higher or additional rate bands.
However, this is not a simple solution. Moving a property from personal ownership to a company is legally a sale. This typically triggers Stamp Duty Land Tax (including the additional 3% surcharge for second properties) and Capital Gains Tax for the individual. Furthermore, mortgage rates for limited companies are often higher than for personal buy-to-let products. Landlords must also consider how they will get the money out of the company, as they will pay Dividend Tax on any profit they draw as personal income.
Practical Next Steps for Landlords
For those managing property in their own names, there are few ways to mitigate the impact of Section 24 without radical changes to ownership. One option is to ensure every other allowable expense is meticulously tracked and claimed. This includes repairs, maintenance, safety certificates, insurance, and travel specifically for property management. The more you can legitimately reduce the initial profit figure, the less impact the finance cost restriction has.
Another consideration is property ownership split. If a property is owned by a married couple or civil partners where one partner is in a lower tax bracket, it might be possible to adjust the ownership proportions (notified to HMRC via a Form 17) so that more of the income is attributed to the person with the lower marginal rate. However, this requires a genuine change in the beneficial interest of the property and should only be done following professional guidance.
Finally, landlords should review their mortgage deals regularly. Since the relief is capped at 20%, a high interest rate is particularly punishing for higher rate taxpayers. Ensuring you are on the most competitive rate possible is the most direct way to reduce the gross interest paid and, consequently, the portion of that interest that is effectively 'un-relieved' by the tax system. Always consult a qualified tax professional to assess how these rules interact with your specific financial circumstances.