HMRC Landlord Crackdown: Letting Agents Urged to Push Voluntary Disclosure

Letting agents have been urged to take a proactive approach in helping their landlord clients meet their tax obligations, following record-breaking results from HMRC’s latest Let Property Campaign.

According to new data, HMRC recovered £107 million in unpaid taxes from Buy-to-Let landlords in 2024/25. This is the highest total on record. The figure represents a doubling of repayments compared to three years ago, signalling a renewed determination by HMRC to clamp down on undeclared rental income across the private sector.

Impact of HMRC Landlord Crackdown

The Let Property Campaign is one of HMRC’s most prominent disclosure initiatives, targeting landlords who have failed to declare some or all of their rental income. Rather than relying solely on formal investigations, the scheme encourages landlords to voluntarily come forward, disclose outstanding liabilities and settle them on more favourable terms.

This approach has proven effective, with rising repayments each year suggesting both improved awareness and increased enforcement. Experts say HMRC’s growing access to digital data from online platforms, letting agents and financial institutions has made it easier to identify non-compliant landlords, giving property professionals a stronger incentive to guide clients toward compliance before being contacted by HMRC directly.

What Can Letting Agents Do to Help?

Agents have been encouraged to view HMRC’s campaign as an opportunity to strengthen client relationships through transparency and responsible guidance. Complex and frequently changing tax rules, such as restrictions on mortgage interest relief, can easily result in “phantom profits,” where landlords appear to earn more on paper than they actually do, leading to higher tax liabilities and potential reporting errors.

To help landlords avoid penalties, letting agents are recommended to take three key steps:

• Remind landlords that all rental income must be declared, including income from short-term lets and shared ownership
• Encourage landlords to use HMRC’s online Self Assessment tools to check if they need to submit a return
• Direct clients with undeclared income to the Let Property Campaign for voluntary disclosure before HMRC intervenes

Early cooperation can substantially reduce fines and prevent more serious consequences, such as formal investigations or criminal proceedings.

Penalties for Ignoring the Let Property Campaign

While voluntary disclosure offers reduced penalties, landlords who fail to come forward risk facing higher fines or public enforcement action once identified. HMRC’s data-obtaining powers have expanded in recent years, giving the department access to information from letting platforms, property registers and even overseas records.

Experts warn that landlords who assume their undeclared income will go unnoticed are increasingly taking a gamble. The Let Property Campaign operates year-round, meaning that disclosures can be made at any time. This is a flexibility that HMRC says should make compliance easier for landlords willing to act before formal intervention.

In addition to financial penalties, failing to disclose can damage a landlord’s credibility with lenders and tenants. It is important to note that agents have a professional duty to promote compliance and ensure their advice helps landlords avoid unnecessary risks.

How Will Things Change in the Future?

The recent surge in repayments highlights a wider shift in HMRC’s approach — from reactive enforcement to proactive prevention. Rather than waiting for errors to occur, the department is using technology and partnerships with the property sector to detect inconsistencies early.

For letting agents, this change means playing a more strategic role. By integrating tax awareness into client onboarding or management discussions, agents can protect both landlords and their own reputation within a property sector increasingly under scrutiny.

It is believed that better education on issues such as mortgage interest relief, capital gains obligations and deductible expenses will go a long way toward improving compliance. Agents who offer this level of support are likely to build stronger, more trusted relationships with their landlord clients.

Conclusion

As HMRC’s Let Property Campaign gains traction, the message to landlords and letting agents alike is clear — disclose early, disclose fully and stay compliant. The record £107 million recovered this year underscores the growing effectiveness of data-driven enforcement and the value of voluntary cooperation.

For agents, guiding clients through this process isn’t just about avoiding penalties; it’s about reinforcing professionalism and integrity in an evolving rental landscape. The line between honest oversight and deliberate avoidance is thinner than ever and the cost of ignoring it continues to rise.