Selling the property was the simple part. The 60-day tax deadline was the part nobody mentioned.
The Scenario
You bought a small terraced house in Twickenham in 2008. You lived there for the first few years of your marriage, then moved to a larger family home as the children arrived, and let the original property out. It has been a steady source of income ever since, with the same managing agent for most of that time and a sequence of considerate tenants. Now, after seventeen years and a quietly impressive rise in value, you decide to sell.
Completion takes place on 7 February 2026. The solicitor handles the legal side, the estate agent waves you off, and you turn your attention to what to do with the proceeds.
Three weeks later, an accountant friend mentions, almost in passing, that you have probably already missed a tax deadline. You have not heard of any tax deadline. The completion was, by your reckoning, the end of the matter.
At a Glance
- Client profile: Richmond-based married couple, joint owners of a former main residence in Twickenham, let out since 2012
- Situation: Sale of long-held UK residential property; 60-day CGT reporting deadline missed by approximately three weeks at first contact
- Core issue: Late filing of the CGT return, incomplete records of original purchase costs and capital improvements, uncertainty over Private Residence Relief
- Cause: No mention of the 60-day requirement during the conveyancing process, no prior experience of capital gains reporting
- Resolution: Late filing of both individual CGT returns, full allowable cost reconstruction, PRR claimed for residential period and final period exemption, fixed late-filing penalty applied
- Time to resolve: Approximately four weeks from first meeting to HMRC accepting both returns
Why this happens more often than you might think
For a deadline that bites quickly and applies very widely, the 60-day CGT reporting requirement is remarkably under-publicised. It came into force in 2020, originally as a 30-day window, and was extended to 60 days following representations from the conveyancing profession that the original window was simply too tight to comply with in practice. Even with the longer window, the awareness gap among property owners is striking. Most people we speak to have never heard of the requirement until they are already inside it, or already past it.
The requirement applies to any UK resident disposing of UK residential property where CGT is due on the disposal. It runs from the date of completion, not the date of exchange.
Both the report and the payment of estimated tax are due within sixty days of completion. Penalties can arise as soon as the 60-day deadline is missed. In some cases a reasonable excuse may support an appeal against a penalty, but sellers should not rely on this. The safest approach is to assume the report and payment are due within 60 days of completion.
What makes the requirement so easy to miss is that nothing in the conveyancing process is designed to flag it. The various professionals involved in a property sale are, in most cases, not the people who will tell you about it:
- Solicitors will sometimes mention it as a courtesy, but they are not obligated to provide tax advice and most do not.
- Estate agents have no role in tax compliance.
- Mortgage lenders will not raise it at any stage of the discharge process.
- Conveyancers occasionally include a generic line in their completion pack, but rarely as a flagged action point.
Unless the seller has already engaged an accountant or has past experience of CGT reporting, the 60-day window can pass entirely unnoticed. For owner-occupiers selling their main home, none of this matters, because the gain is wholly relieved by Private Residence Relief and there is no CGT due. For landlords, second-home owners, and anyone disposing of a property that has not been their main residence for the entire ownership period, the requirement is live where CGT is due, and the penalties for missing the deadline begin at £100 and escalate from there.
This is the gap that the companion article How to Keep Property Records That Will Save You Money When You Sell was written to address. The reporting requirement and the records that support it sit either side of the same problem.
Why the records matter as much as the deadline
The 60-day deadline gets the headlines, but the deeper challenge in practice is usually the calculation itself.
To work out a chargeable gain accurately, you need a clear record of:
- The original purchase price
- Incidental acquisition costs, such as solicitor’s fees, Stamp Duty Land Tax, and valuation or survey fees where directly connected with the acquisition
- Capital improvements made during ownership (extensions, structural works, kitchen and bathroom refits where they go beyond routine repair)
- Incidental disposal costs, such as estate agent and legal fees
Without those records, the gain may be overstated and the tax overpaid. It may be possible to correct a return later, but that is less efficient than submitting a properly evidenced calculation in the first place. For a property held since 2008, the records are almost always incomplete.
Memory fades. Filing systems change. Old solicitors retire. Mortgage providers merge. The original SDLT receipt is in a box in the loft, if it has not been thrown out during a house move. Some of the improvements were carried out by tradespeople who were paid in cash and never issued an invoice. The temptation, when faced with this archaeological task, is to give up and use the headline gain. That decision can cost real money.
“When clients tell us they have no records, what they almost always mean is that they have not yet looked properly. The records exist, often in five different places, but they require methodical reconstruction. We have not yet seen a case where the gain could not be meaningfully reduced once we worked through this carefully.”
How the scenario unfolded
The situation described above is drawn from composite client experience rather than any single individual. The details, however, are typical of how these cases develop, and the emotional pattern is one we recognise quickly.
The couple in question, both in their early sixties, had bought the Twickenham terrace in 2008 for £427,000. They lived in it for the first four years of their marriage, then moved to a larger property in Richmond in 2012 as their first child was on the way. They let the original house through a managing agent for the next thirteen years, and sold it with completion on 7 February 2026 for £812,000.
The headline movement in value, before any costs or reliefs, was £385,000.
When they came to see our personal tax planning team, it was already early May, approximately three weeks past the 8 April 2026 deadline. They were unsettled rather than panicked, but they had no idea what they were facing. The property was held jointly, so the gain was split equally, and each spouse had a separate filing obligation.
The first conversation was diagnostic rather than technical. We asked what records they had, what improvements had been made, when they had moved out, and whether the property had been let throughout the period from 2012 onwards. The answers were partial, but they pointed clearly to the work that needed to happen.
“Most of the anxiety with these cases is about the unknown rather than the actual liability. Once you can see the calculation taking shape, even before it is finalised, the stress drops considerably. A figure you can work with is always easier than a figure you are imagining.”
What the process involved
We registered as their tax agents and began reconstructing the cost base. The original purchase records were partial. They had a copy of the completion statement, which gave us the SDLT figure and the legal fees, but the survey invoice was missing. We approached the original surveyor’s firm, which still existed under a slightly different name, and they retrieved a copy from their archive. The total of the incidental acquisition costs came to just under £19,000, all of which was deductible.
Capital improvements were the harder piece.
The couple had extended the kitchen in 2014 and refitted the bathroom in 2018. They had paid the kitchen builder by bank transfer, which meant we could pull the bank statement and pair it with email correspondence as evidence. The bathroom had been paid partly by card and partly in cash, with no surviving invoice. We could substantiate the card portion but not the cash element. We took the view that only the substantiated costs should be claimed, which is the correct approach, and the figure for capital improvements settled at approximately £42,000.
The disposal costs were straightforward. The estate agent’s commission and solicitor’s fees were all on the completion statement and totalled around £14,000.
The next question was Private Residence Relief.
The couple had occupied the property as their main home from completion in May 2008 to September 2012, a period of 52 months. The total ownership period from completion to disposal was 213 months. PRR applied to the 52 months of actual occupation plus the final 9 months of ownership, giving a relieved fraction of 61 months out of 213. The remaining 152 months were chargeable.
Pulling all of that together produced the following position:
- Sale proceeds, net of disposal costs: £798,000
- Less: original purchase price and incidental acquisition costs (£427,000 + £19,000): £446,000
- Less: substantiated capital improvements: £42,000
- Gross gain before reliefs: £310,000
- Less: PRR relief at 61/213 of the gain: £88,732
- Chargeable gain after PRR: £221,268
- Per spouse, on equal joint ownership: £110,634
- Less: each spouse’s annual exempt amount of £3,000
- Taxable gain per spouse: £107,634
With both spouses in the higher rate band and the residential property CGT higher rate of 24 per cent applying, the combined CGT liability was approximately £51,664 before late-payment interest and the fixed penalties. That figure was materially below what the couple had imagined when they first walked in. The gap between expectation and reality is, in our experience, the rule rather than the exception.
A point worth pausing on: spouses are taxed individually on capital gains. The annual exempt amount is per person, not per couple, and where a property is jointly owned, each spouse files separately. This is one of the few features of the CGT regime that works in favour of married couples without any planning.
We submitted both individual CGT returns through HMRC’s online property reporting service. Because the filing was made approximately three weeks after the 60-day deadline, only the initial fixed £100 late filing penalty applied to each spouse, with no daily penalties having yet accrued. Late payment interest was due on the tax, calculated from the original deadline to the date of payment. The total of penalties and interest, while not negligible, was a small fraction of the saving achieved by claiming the allowable costs and PRR properly.
What this case teaches about the 60-day window
The headline lesson is straightforward. Anyone selling UK residential property where CGT is due should treat the 60-day deadline as a live obligation from the moment a sale is contemplated.
That means engaging an accountant before completion, not afterwards.
The deeper lesson concerns records. The cost base of a property held for fifteen or twenty years is rarely sitting in a single tidy folder. It has to be reconstructed, and reconstruction takes time. The earlier the work begins, the better the outcome. The companion article Key Factors Affecting Richmond Businesses and Taxpayers in 2026 sets out the wider environment in which these obligations now sit.
There is also a quieter point about the value of professional support before, rather than after, completion. A short conversation with our tax planning team during the listing phase can establish the cost base, identify the PRR position, model the expected liability, and ensure the 60-day return is submitted on time without panic.
The emotional dimension
Tax professionals sometimes underestimate the psychological weight of HMRC paperwork. For someone with no prior experience of CGT reporting, the discovery that they have missed a deadline they did not know existed produces a particular kind of distress.
It is not financial fear so much as a sense of having been caught out by a system that was supposed to be straightforward. Selling a house should be a closed transaction, not an opening of a new compliance burden. Most clients who arrive in this position are not careless. They have done the conveyancing properly, paid the agent, transferred the funds, and assumed the matter was concluded. Discovering that a separate tax obligation runs in parallel to the conveyancing, and that the deadline has already passed, feels like an ambush.
That feeling is not irrational, but it is almost always disproportionate to the actual exposure once the calculation is properly worked through.
The shift from anxiety to clarity, which usually happens within the first meeting, is often the most important part of the engagement. The numbers matter, but the relief of understanding the situation properly matters at least as much.
What changes afterwards
Once both returns are filed and accepted, and the tax and penalties paid, the matter is closed. The couple now have a clear picture of how property disposals work for tax purposes, which is useful given that they still hold a small portfolio of two further buy-to-let properties they may eventually sell. We agreed an annual review of the cost base on those remaining properties, so that any future disposal can be reported within 60 days without difficulty.
For other landlords in Richmond, Twickenham, and Kingston, the wider lesson is that the conveyancing process will not protect you from a missed CGT obligation.
The protection has to come from your own awareness, or from someone you have asked to think about it on your behalf. Most of our landlord clients now build a short pre-disposal review into their property management routine. It costs very little and removes the risk of a similar surprise.
Frequently asked questions
What is the 60-day Capital Gains Tax reporting rule?
The 60-day rule requires UK residents to report and pay any CGT due on the disposal of UK residential property within 60 days of completion. The report is made through HMRC’s online property reporting service, and the tax is paid as an estimated amount based on the figures available at the time. The rule applies to second homes, buy-to-let properties, inherited properties being sold, and any other residential disposal where CGT is due on the gain.
Does the 60-day deadline run from exchange or completion?
Completion. The clock starts on the date of completion, not the date of exchange. For most transactions this gives a few extra weeks, because exchange and completion are usually separated by a fortnight or more, but it does mean you cannot start counting from the moment the deal feels done in principle.
What happens if I miss the 60-day CGT deadline?
HMRC issues a fixed late filing penalty of £100 once the deadline passes. If the return remains outstanding for three months, daily penalties of £10 per day begin to accrue, capped at £900. Further penalties, calculated as a percentage of the tax due, apply at six and twelve months overdue. Late payment interest is also charged on any tax that should have been paid within the 60-day window. In some cases a reasonable excuse may support an appeal against a penalty, but the safest approach is to file and pay on time.
Do I still need to report if there is no tax to pay?
Where CGT is due on the disposal, the return and payment are normally required within 60 days. If the gain is fully covered by Private Residence Relief, losses, or the annual exempt amount such that no CGT is due, the reporting position should be checked before assuming no return is needed. The rules in this area are worth confirming with a tax adviser, particularly where multiple reliefs or losses are involved.
What costs can I deduct when calculating Capital Gains Tax on a property sale?
Allowable deductions include the original purchase price, incidental acquisition costs such as solicitor’s fees, Stamp Duty Land Tax, and valuation or survey fees where directly connected with the acquisition, the cost of capital improvements made during ownership such as extensions or structural works, and incidental disposal costs such as estate agent and legal fees. Routine repairs, maintenance, and mortgage interest are not deductible against the capital gain.
Can I claim Private Residence Relief if I lived in the property only for part of the time?
Yes. PRR applies on a pro-rata basis, calculated by reference to the months of actual occupation as your main residence, plus the final 9 months of ownership which are exempt regardless of whether you lived there at the time. If you lived in the property for 4 years out of a 17-year ownership period, the relief covers those 4 years plus the final 9 months. The remaining months are chargeable.
Do my spouse and I file the same CGT return for a jointly owned property?
No. Spouses are taxed individually on capital gains, and where a property is held jointly, each spouse files a separate CGT return covering their share of the gain. Each spouse is also entitled to their own annual exempt amount, currently £3,000. This is one of the few features of the regime that works in favour of married couples without any planning required.
What if I don't have records of the original purchase or improvement costs?
The records can almost always be reconstructed with some patience. Original solicitors and surveyors often retain archives going back a decade or more. Bank statements can substantiate payments to contractors. SDLT records can be requested from HMRC. The reconstruction takes time but is rarely impossible, and the tax saving usually more than justifies the effort.
If this feels familiar
If you are contemplating the sale of a UK residential property that has not been your main home for the entire ownership period, or if you have already completed and are uncertain about the reporting position, a short conversation with someone who understands the 60-day requirement and the supporting calculation is usually the most useful next step.
Our team in Richmond works with landlords and property owners across the south-west London area. A calm conversation early in the process is almost always less expensive than a remediation conversation after the deadline has passed. If you would like to talk through your position, you are welcome to get in touch.
About the author
Donovan Crutchfield, Area Managing Partner, Xeinadin Richmond
LinkedIn: Connect with Donovan on LinkedIn.
Donovan works with owner-managed businesses and private individuals across Richmond-upon-Thames and the wider South West London catchment. His practice includes a significant proportion of property-owning clients managing the intersection of long-term holdings, capital gains exposure, and HMRC reporting obligations.
This case study is based on composite client experience and does not represent any single individual. All identifying details have been changed. The information provided is for general guidance only and should not be treated as a substitute for professional tax advice specific to your circumstances.
