Why CGT private residence relief claims fail: 5 common reasons (UK 2026)

When someone sells a property in the UK that has not been their only or main home for the entire period of ownership, Capital Gains Tax can apply to the gain. Private Residence Relief (PRR), set out in sections 222 to 226 of the Taxation of Chargeable Gains Act 1992 (TCGA 1992), is the main way that liability is reduced or eliminated. For most owner-occupiers selling the one house they have always lived in, PRR shelters the full gain automatically. The complications arise when ownership history is less tidy — a let period, a long absence, a large garden, partial business use, or a delay between leaving the property and completing the sale.

Where the relief is reduced or refused, HMRC enquiries and First-tier Tribunal appeals tend to turn on the same recurring legal points. This guide walks through five of the most common reasons PRR claims fail in the 2026 tax year, anchored on HMRC's published Capital Gains Manual (CG64200 onwards), HMRC's helpsheet HS283 Private Residence Relief, and the statutory framework in TCGA 1992. It is general information and not advice. Speak to a qualified tax adviser before acting on any CGT position.

The size of the population at issue

The UK property market generated 921,873 residential transactions in England and Wales in 2024 alone, according to HM Land Registry's Price Paid dataset. Not all of those involve a CGT computation — sales of an owner-occupier's only home are usually fully relieved — but the chargeable slice is large, particularly in higher price bands where landlords and second-home owners cluster.

Source: HM Land Registry Price Paid data, full year 2024 (queried 17 May 2026 from the cleaned dataset underpinning Homecost). The price bands are illustrative of the population in which CGT computations more frequently arise on disposal.

A simple illustration of how quickly gains accrue: the ONS UK House Price Index records the England index at 68.0 in April 2015 and 101.5 in February 2026 — cumulative growth of 49.3% on a single regional series. A property bought as a buy-to-let in 2015 for £225,000 and sold in 2026 at the same percentage uplift would carry a notional gain of around £111,000 before any PRR or letting periods are considered. Where part of that ownership was let, mixed-use, or absent, the question becomes how much of that gain PRR shelters.

Reason 1: The final-period exemption is miscounted

Many claims rely on what owners refer to (often informally) as the "36-month rule" — the long-standing concession that the last 36 months of ownership are treated as a period of occupation regardless of whether the owner actually lived there. That figure has not been correct for general claims for more than five years.

Finance Act 2020 reduced the final-period exemption for disposals from 6 April 2020 onwards to 9 months, down from 18 months (which itself replaced the 36-month rule for disposals from 6 April 2014). HMRC's manual confirms the position at CG64985.

A 36-month final-period exemption still applies in two narrow cases:

• The owner (or their spouse or civil partner) is a long-term resident in a care home; or
• The owner is disabled or in receipt of certain disability-related benefits, on the conditions set out in s.225E TCGA 1992.

Claims that assume a 36-month tail without meeting those conditions are routinely reduced on enquiry. Where the property was let for the final two years before sale, the gap between "9 months relieved" and "36 months relieved" can represent a five-figure CGT liability on a typical English property. See HMRC's helpsheet HS283 for the worked apportionment.

Reason 2: Lettings relief is no longer available unless the owner shared occupation

Lettings relief — formerly worth up to £40,000 of additional shelter per owner under s.223(4) TCGA 1992 — was significantly restricted from 6 April 2020. The current position is set out at HMRC CG64710: lettings relief now applies only to periods of let occupation where the owner was in shared occupation with the tenant in the same dwelling.

The practical effect is that a landlord who moved out before letting the property — which describes the vast majority of small landlords — can no longer claim lettings relief on any disposal from 6 April 2020 onwards, irrespective of how the property was treated before that date.

A common failure pattern: an owner letting a former main residence for the last several years assumes that lettings relief still tops up the period of absence. On enquiry HMRC applies the post-2020 rules to the entire disposal, and the relief is refused. The calculation is unaffected by how the lettings relief would have looked under the pre-2020 rules.

Reason 3: The garden and grounds exceed the 0.5-hectare permitted area

Section 222(2) and (3) TCGA 1992 limits PRR on garden and grounds to a "permitted area" of 0.5 of a hectare (approximately 1.24 acres), including the site of the dwelling. A larger area can be relieved only where HMRC accepts that the additional land is required for the "reasonable enjoyment of the dwelling-house as a residence" having regard to its size and character.

HMRC's manual at CG64822 sets out the tests, and the Longson v Baker (2001) line of cases is the principal authority cited on the "required for reasonable enjoyment" point. Two recurring problems cause claims to fail:

• Selling off a plot before the main house. Once the dwelling has been disposed of, any later sale of severed land falls outside PRR entirely, because the land is no longer being sold "with" or "as part of" the residence (CG64377).
• Houses with paddocks, orchards or outbuildings. Where the additional land is used for non-domestic purposes — grazing, stables operated commercially, outbuildings let separately — HMRC routinely treats that area as non-qualifying.

For larger rural plots in particular this is the issue most likely to produce a partial restriction rather than a full refusal.

Reason 4: Periods of absence require an actual return to occupation

TCGA 1992 s.223 deems certain periods of absence to be periods of occupation for PRR purposes, provided the property was the owner's only or main residence both before and after the absence. The three statutory categories, summarised at HMRC CG65030, are:

• Any period of absence not exceeding three years in total, for any reason;
• Periods of absence (any length) during which the owner worked abroad in an employment carried out wholly abroad;
• Periods of absence not exceeding four years during which the owner could not occupy the property because their employment required them to live elsewhere in the UK.

The trap is the "return to occupy" requirement. If the owner does not actually move back into the property as their main residence after the absence, none of the deemed-occupation provisions apply to that period. Claims fail when the owner sells the property without returning, particularly on long-term overseas postings or where the property is let throughout the absence and then sold from outside the UK.

A limited concession (ESC D4) used to relax the post-absence occupation requirement where return was prevented by employment. HMRC's manual confirms it continues to apply in narrow circumstances; the safer reading is that any non-return is a material risk to the s.223 claim.

Reason 5: The property never qualified as a "residence" in the first place

Whether a dwelling was the owner's residence at all is a question of fact, and case law shows that mere ownership and occasional occupation is not enough. The leading authority is Goodwin v Curtis (1998) — a Court of Appeal decision in which a five-week occupation of a recently purchased property was held to be insufficient to constitute a "residence" for PRR purposes. HMRC summarises the position at CG64435: the occupation must have a degree of "quality, permanence and expectation of continuity".

Two patterns lead to claims being refused on this ground:

• Brief occupation around a sale. Moving into a property for a short period immediately before disposal, with no genuine change of residence, will not retrospectively make that property a residence for PRR. The intent and quality of occupation are tested on the facts.
• Multiple properties without an election. Where a taxpayer owns and uses more than one dwelling as a residence, s.222(5) allows a nomination of which is to be treated as the main residence, made within two years of acquiring the second property. Failure to make the election in time means HMRC determines the main residence on the facts, and the owner loses the certainty of choosing.

Claims also fail where the property was, in substance, an investment from acquisition — bought to refurbish and resell, or bought via a corporate structure with the individual never being the legal beneficial occupier. PRR is specific to individuals occupying as their residence.

Beyond the five reasons: the 60-day reporting deadline

A separate compliance issue, frequently overlooked, sits alongside the PRR computation. Since 27 October 2021, UK residents disposing of UK residential property on which CGT is payable must file a CGT on UK Property Return within 60 days of completion and pay the tax due in the same window. Where PRR fully shelters the gain, no return is required; where it does not, late filing triggers automatic penalties under Schedule 55 Finance Act 2009 regardless of the strength of the underlying PRR claim.

Penalties begin at £100 for failure to notify on time and escalate after three months. Interest accrues on any unpaid tax from the 61st day after completion. The 60-day deadline is unusual in UK tax — it is materially shorter than the Self Assessment timetable buyers and sellers may be more familiar with — and it is one of the most common reasons CGT enquiries open in the first place.

What this means for sellers in 2026

For owner-occupiers selling the only home they have lived in, PRR will usually shelter the full gain and these issues do not arise. They become important where any part of the ownership history involves letting, absence, partial business use, or larger plots — exactly the situations that the underlying statute and HMRC guidance are designed to police.

If you are weighing up the sale of a let property, a former main residence, or a property with significant grounds, three points are worth taking from the case-law pattern above:

• The relevant rules are the ones in force on the date of disposal, not the rules in force when the property was first occupied or let. Historic concessions may no longer apply.
• The arithmetic apportions the gain over the whole period of ownership — the longer the property has been held in a chargeable use, the larger the slice of the gain that falls outside PRR.
• Reporting and payment are due within 60 days of completion where any CGT is payable. The PRR claim and the return are separate but tightly linked compliance steps.

A worked example for any specific transaction depends on the dates of occupation, the dates of letting or absence, the apportionment of the gain, and the owner's other CGT positions in the year. For a calm starting point on what the headline numbers might look like on a particular property, Homecost can be used to pull the recorded transaction history and floor area: try the Westminster sample at /?postcode=SW1A+1AA, or read the related guides on the additional property stamp duty surcharge, the SDLT higher-rate refund refusals, and the full cost of buy-to-let in 2026. The full library of cost guides is at /blog.

This guide is general information and not personal tax advice. Always speak to a qualified tax adviser, conveyancer or accountant before acting on a CGT position or filing a 60-day return.