Property tax cases: where the tax bill came down

The cases below are worked examples built from the rules and rates in force for 2026/27 and the penalty ranges HMRC publishes. They are typical of the landlord work we do, with figures rounded and details generalised; they are not accounts of identifiable clients and no client information appears here.

We do not publish savings we cannot evidence. If you want figures for a situation that looks like yours, send the facts and we will run the numbers on your own position before you commit to anything.

The position: a South London landlord with two let flats had never reported the rent, believing the mortgage payments cancelled out the income. Roughly six years had passed. The mortgage capital element is not deductible, so there was real profit; the interest element only ever produced a 20% reducer.

What changed the outcome: coming forward unprompted through the Let Property Campaign, and evidencing carelessness rather than deliberate conduct. That kept the disclosure inside the six-year window instead of twenty, and moved the penalty into the unprompted careless range, which starts at nil and is capped well below the prompted equivalent.

Where the money was saved: three deduction categories the landlord had never claimed, letting agent commission, safety certificates and insurance, and replacement of domestic items relief on white goods and furniture, cut the taxable profit for every year. Interest still ran on the tax, but the penalty was the smaller part of the settlement rather than the larger one.

The lesson: the behaviour analysis and the disclosure window are worth more than any single receipt. Argue them properly at the start, in writing.

The position: a UK-resident owner of an apartment abroad had paid local tax on the rent and assumed nothing was due here. A nudge letter arrived after HMRC received account data under the Common Reporting Standard.

What changed the outcome: recomputing the profit under UK rules rather than the foreign return, then claiming double taxation relief for the overseas tax already paid. Credit relief is capped at the UK tax on the same income, but here it removed most of the liability that the raw foreign figures had implied.

Where the money was saved: sterling conversion at the correct rates, UK-basis deductions the foreign return had not allowed, and a properly evidenced behaviour position on an offshore matter, where penalty bands are otherwise far higher than domestic ones.

The lesson: a nudge letter is not an assessment. The tax that eventually falls due is often a fraction of the gross rent HMRC can see, provided the disclosure is prepared rather than guessed.

The position: a higher-rate landlord with four mortgaged properties was paying tax on more than the real profit because finance costs only attract a 20% reducer personally.

What the review covered: corporation tax at 19% to 25% with interest fully deductible inside a company, against the cost of getting there, capital gains on transfer, additional-dwelling stamp duty at 5% on top of standard rates, lender terms and the second layer of tax when profits are drawn as dividends.

The outcome: incorporation only paid for itself where the profits were being retained and reinvested rather than spent. For the landlord drawing everything out, staying personally owned and tightening the expense claim was the cheaper answer.

The lesson: incorporation is a cash-flow and time-horizon decision, not a tax trick. Anyone who tells you it always saves tax has not modelled the exit.

Rental statements or bank records for the years in question, mortgage interest certificates, purchase and improvement costs, and any HMRC correspondence you have received. From that we can tell you which years are in scope, roughly what the tax and penalty range looks like and what the disclosure will cost, before you appoint anyone.

Basic tax advice is free. Computations, disclosures, HMRC correspondence and written advice are chargeable and quoted in writing before work starts.