HMRC are targeting landlords who are not declaring their rental income.
The amount you earn from leasing property must be included in your overall income. This includes entire houses, flats and holiday lets. You must declare this using the self assessment tax return system. This applies, even if you are otherwise paid through PAYE employment and don’t use the self assessment process for anything else.
Why do I have to declare my rental income?
All of your income sources must be declared so that HMRC can apply the correct level of income tax to your situation. If you are not taxed at the correct rate, on your full income amount, then you could owe HMRC unpaid tax. You could also end up paying too much tax and need to submit a tax rebate claim to get it back.
If you are a landlord or non resident landlord you should make sure you are declaring all of your rental income to avoid penalties and an HMRC investigation.