If you’re a landlord who has received income from residential property that hasn’t been fully declared to HMRC, now is the time to act, and act wisely.

The Let Property Campaign is HMRC’s long-running initiative designed to encourage landlords to bring their tax affairs up to date. It offers those who come forward voluntarily the chance to resolve unpaid tax liabilities under more favourable terms than would otherwise be available during a formal investigation. But the process isn’t as simple as completing a form, and without the right guidance, landlords can make costly mistakes or fail to meet HMRC’s expectations.

Understanding the Campaign

The campaign is aimed at individuals who let out residential property and have not declared some or all of their rental income. This could include people renting out a single flat, those with a portfolio of buy-to-let properties, individuals earning above the rent-a-room threshold, or those letting out holiday homes. It also applies to landlords who live abroad while renting out UK properties, and to people who have inherited a property and decided to let it.

What’s not always understood is that even casual or short-term letting can give rise to a tax liability. Many landlords caught out by the rules weren’t aware that income needed to be declared, particularly if they considered it minor or infrequent. Unfortunately, HMRC takes a different view.

Why This Is Becoming More Urgent

In recent years, HMRC has significantly expanded its use of data to identify landlords who may not have declared all their income. Information is routinely cross-checked with Land Registry records, letting agents, deposit protection schemes, mortgage lenders, and even overseas tax authorities. In other words, the chances of going unnoticed have diminished considerably.

Those who choose to come forward voluntarily under the Let Property Campaign are likely to receive lower penalties and avoid more serious consequences such as criminal investigation or a formal tax enquiry. But once HMRC makes first contact, these more lenient terms are generally off the table.

What Happens If You Do Nothing

The risks of inaction can be severe. Landlords who fail to disclose undeclared income could face penalties of up to 100% of the tax owed, in addition to interest on late payments. In cases of deliberate evasion, HMRC can go back up to 20 years and may even pursue criminal proceedings.

Often, landlords think their situation is too minor to be noticed, a single property rented out years ago, or occasional income that felt insignificant at the time. But HMRC's powers are wide-ranging, and its data matching systems are highly effective. If you suspect there's undeclared income in your past, taking control early can make all the difference.

The Value of Professional Advice

Making a disclosure under the Let Property Campaign requires careful preparation. You’ll need to calculate your taxable rental profits accurately, taking into account allowable expenses across each relevant tax year. If records are incomplete, they may need to be reconstructed. You’ll also need to understand how HMRC applies penalties, and ensure your disclosure meets the required legal and procedural standards.

This is where a qualified tax advisor adds real value. From reviewing your rental history and preparing accurate calculations, to managing all communication with HMRC and ensuring your disclosure is complete, professional support can make the process smoother, safer, and far less stressful.

Most importantly, an advisor can help ensure that once your disclosure is accepted, the matter is closed — giving you confidence and peace of mind moving forward.

Speak to Us in Confidence

If you’re a landlord with undeclared rental income — whether recent or historic — now is the time to take advice. The Let Property Campaign won’t last forever, and the longer issues are left unresolved, the greater the potential consequences.

We’ve helped many clients make successful disclosures and settle their tax affairs discreetly and efficiently. Every case is different, and the sooner you seek guidance, the more options you’re likely to have.

Get in touch today for a confidential, no-obligation conversation.