Section 24 Mortgage Interest Relief Explained: What Landlords Need to Know
By Sardar Muhammad, AAT • • 10 min read
⚠️ Important: Section 24 is Now Fully in Effect
The phasing-in period ended in April 2020. Individual landlords now receive only a 20% tax credit for mortgage interest, not a full deduction. This means higher-rate taxpayers pay significantly more tax.
What is Section 24?
Section 24 of the Finance (No. 2) Act 2015 fundamentally changed how individual landlords are taxed on their rental income. Before this change, landlords could deduct mortgage interest from rental income as an expense. Now, they can't.
The Old System (Pre-2017)
- Deduct mortgage interest from rental income
- Pay tax only on the profit after interest
- Higher-rate taxpayers got 40% relief
The New System (2020 Onwards)
- Cannot deduct mortgage interest from income
- Pay tax on rental income before interest
- Receive a 20% tax credit for mortgage interest
- Higher-rate taxpayers only get 20% relief
How Section 24 Increases Your Tax Bill
Let me show you with a real example:
❌ Old System
Rental income: £15,000
Mortgage interest: £8,000
Other expenses: £2,000
Taxable profit: £5,000
Tax at 40%: £2,000
✓ New System (Section 24)
Rental income: £15,000
Other expenses: £2,000
Taxable profit: £13,000
Tax at 40%: £5,200
20% tax credit: -£1,600
Final tax: £3,600 (+£1,600 extra!)
In this example, the landlord pays £1,600 more tax under Section 24 – that's 80% more!
Who is Affected by Section 24?
❌ Affected
- Individual landlords
- Partnerships (personal)
- Trusts
- Buy-to-let investors
✓ NOT Affected
- Limited companies
- Furnished holiday lets
- Commercial property
- LLPs
The Hidden "Tax Trap" – Pushed into Higher Rate
Section 24 can push landlords into a higher tax bracket, even when profits haven't increased:
Example: Pushed into Higher Rate
Salary: £40,000
Rental income: £20,000
Mortgage interest: £12,000
Old taxable income: £40,000 + £8,000 = £48,000 (basic rate)
New taxable income: £40,000 + £20,000 = £60,000 (higher rate!)
The landlord is now taxed at 40% on income that previously didn't exist for tax purposes.
This can also affect:
- Child Benefit (starts being clawed back above £50,000)
- Personal allowance (reduced above £100,000)
- Student loan repayments
Strategies to Mitigate Section 24
1. Transfer to a Limited Company
Companies can still deduct mortgage interest as an expense. However, this triggers:
- Stamp Duty Land Tax (SDLT) on transfer
- Capital Gains Tax on the "sale" to company
- Additional administration and filing requirements
This may only make sense for high-value portfolios with long-term investment horizons.
2. Transfer Ownership to Lower-Earning Spouse
If one spouse pays basic rate and the other pays higher rate, transferring beneficial ownership can reduce the family tax bill. Use a Declaration of Trust to split income differently from legal ownership.
3. Pay Down Mortgages
Less mortgage = less interest = less impact from Section 24. Consider using rental profits to reduce debt.
4. Review Your Portfolio
Some properties may no longer be profitable after Section 24. It may be worth selling highly-leveraged properties and keeping those with lower mortgages.
5. Consider Furnished Holiday Lets
FHLs are exempt from Section 24 and receive additional tax benefits. If your property is in a tourist area, this could be an option.
Frequently Asked Questions
What is Section 24?
Section 24 restricts mortgage interest relief for individual landlords. You can no longer deduct mortgage interest from rental income before calculating tax. Instead, you receive a 20% tax credit.
Does Section 24 apply to limited companies?
No. Section 24 only applies to individual landlords. Limited companies can still deduct mortgage interest as an expense. This is why some landlords have incorporated.
How much extra tax will I pay?
Higher-rate taxpayers pay significantly more. A 40% taxpayer loses 20% relief (40% - 20% credit), so effectively pays 20% more tax on mortgage interest. Additional rate taxpayers lose 25%.
Do You Need Help with Landlord Tax?
Section 24 has made property taxation much more complex. Getting the right advice can save you thousands. I help landlords across Glasgow and Scotland with:
- Self-assessment tax returns
- Tax planning and mitigation strategies
- Incorporation advice
- Income splitting with spouses
Get Expert Landlord Tax Advice
Let me review your property portfolio and find the best strategy to minimise your tax bill under Section 24.
Sardar Muhammad, AAT Certified
Sardar is an AAT certified accountant and founder of LimeTree Accounting Solutions in Glasgow. He specialises in helping landlords navigate property tax complexities including Section 24.