A farmer or landowner who has held a field for decades, and who has fielded (no pun intended) an approach from a housebuilder or promoter about its development potential, often assumes Agricultural Property Relief will simply keep doing what it has always done: shelter the land from Inheritance Tax. It won't, not in full, and the gap that opens up is precisely the part of the value everyone is now most excited about — the development uplift.
What APR actually relieves
Agricultural Property Relief gives up to 100% relief from Inheritance Tax, but only on the agricultural value of qualifying land and buildings — defined as the value the land would have if it were subject to a perpetual covenant restricting it to agricultural use. That is a specific, restricted figure, and it is very often well below the land's open market value, sometimes by a wide margin.
Where a field is genuinely just a field — no planning interest, no realistic prospect of development in the foreseeable future — agricultural value and market value tend to sit close together, and APR does most of the practical work of removing the land from the IHT calculation. The relief was never designed to reach further than that, and HMRC has never treated it as doing so. It relieves farming, not the prospect of development.
Where the gap opens: hope value and development value
The moment a piece of land attracts genuine development interest — a promoter approaches the owner, a call for sites goes out under the local plan, or neighbouring land gets an allocation — its market value can move a long way above its agricultural value. That uplift is usually described as hope value before planning permission exists, and development value once permission is granted or clearly imminent. Either way, none of it is agricultural value, and none of it is relieved by APR.
The practical consequence: a landowner who dies holding land with significant hope or development value has an estate exposed to 40% Inheritance Tax on the whole of that uplift, with only the (usually much smaller) agricultural value sheltered. For a family that has watched land values climb because a promoter has been actively marketing a site for allocation, the IHT exposure can grow faster, and more suddenly, than anyone in the family has planned for — because the growth is happening in exactly the slice of value APR was never built to reach.
Business Property Relief can sometimes step in to cover value APR does not, where the land is used in a qualifying trade rather than let out for agriculture — but that is a different test with its own conditions, and a passive landowner simply waiting on a promoter or option to mature is unlikely to meet it merely because the land has development potential.
How option and promotion agreements change the picture
Landowners frequently enter an option or promotion agreement with a developer well before any sale takes place, sometimes running for a decade or more while planning permission is pursued. Signing that agreement does not, by itself, dispose of the land. The owner typically keeps occupying and farming it, which means agricultural value continues to qualify for APR on exactly the same basis as before the agreement was signed.
What changes is the market value used to measure the unrelieved slice. An option agreement with a housebuilder attached to it signals to any valuer that development value now exists, and the longer the option runs and the closer planning progresses, the larger that hope value component becomes — while the APR-qualifying agricultural value stays essentially static. A landowner can therefore find the unrelieved exposure in their estate growing every year the option sits unexercised, even though nothing about how the land is farmed, or who occupies it, has changed at all. Dying partway through an option period is one of the more common ways this gap is discovered too late, because the family had been thinking about the eventual sale proceeds rather than the estate's exposure in the meantime.
Once the option is exercised and the land is actually sold, the development value crystallises as sale proceeds rather than as an unrealised IHT exposure — at which point the relevant question becomes Capital Gains Tax on the disposal (including, where only part of a holding is sold, the part disposal apportionment rules) rather than APR at all. The IHT exposure specifically sits in the window between hope value emerging and the land actually changing hands.
The £2.5 million cap adds a second layer
From 6 April 2026, the 100% rate of relief for Business Property Relief and Agricultural Property Relief combined is restricted to a shared £2.5 million allowance per estate, transferable between spouses, with the excess relieved at only 50%. This cap sits on top of, not instead of, the agricultural-value restriction described above — it does not change what APR covers, only how generously the part it does cover is relieved once the total exceeds the allowance.
For a working farm with substantial agricultural value alone, the cap can now bite even without any development story at all, simply because the qualifying agricultural value itself exceeds £2.5 million. Layer development-adjacent value on top — some of it APR-qualifying agricultural value pushed toward the cap, some of it wholly unrelieved hope value beyond APR's reach entirely — and a landowner can end up facing three different outcomes across three different slices of the same field: full relief, 50% relief, and no relief at all.
Common mistakes
- Assuming APR shelters the whole market value of land once it has a development story attached to it, rather than only the agricultural value
- Not revaluing the estate's IHT exposure as an option or promotion agreement progresses, leaving a stale valuation that understates the hope value that has since emerged
- Treating an unexercised option as a non-event for IHT purposes because no sale has actually happened yet
- Overlooking that the £2.5 million BPR/APR cap can be exhausted by agricultural value alone on a larger farm, before any development value is even considered
- Leaving lifetime gifting or life insurance planning until a sale is imminent, when the seven-year clock on gifts needs time to run before it offers any protection
What this means for landowners
Anyone holding land that has, or is likely to attract, development interest should treat the agricultural value and the hope or development value as two separate questions for Inheritance Tax purposes — because HMRC does. That means getting a proper split valuation once an approach from a developer or promoter is on the table, revisiting it as an option or promotion agreement progresses, and planning around the exposure in the gap years before a sale actually completes, not after. It sits alongside wider inheritance tax planning for property and land, and it's exactly the kind of cross-over between farming, development and estate planning we work through with landowners and their families.
Common questions
Does Agricultural Property Relief cover development value?
No. Agricultural Property Relief only ever relieves the agricultural value of land, meaning what it would be worth restricted to agricultural use in perpetuity. Any development or hope value above that figure receives no APR at all and is fully exposed to Inheritance Tax at 40% unless a separate relief, such as Business Property Relief, applies to it.
Does entering an option agreement with a developer affect APR?
Signing an option agreement does not itself dispose of the land, so the landowner can continue to occupy and farm it, keeping APR available on the agricultural value while the option runs. But the option premium and the anticipated development uplift increase the land's market value without increasing the agricultural value APR relieves, widening the unrelieved gap that sits in the estate if the owner dies before the option is exercised.
How does the £2.5 million Business Property Relief cap interact with APR?
From 6 April 2026 the 100% rate of relief for Business Property Relief and Agricultural Property Relief combined is capped at £2.5 million per estate, transferable between spouses, with the excess relieved at only 50%. The cap applies on top of, not instead of, the existing restriction that keeps development value out of APR altogether, so land with significant hope value can face both problems: no APR on the uplift at all, and only 50% relief on any BPR-qualifying value above the shared allowance.
Kieran Holsgrove is a Director and Co-Founder of Grafene Accounting, the property tax specialist firm based in Liverpool. He advises property developers, investors and landlords across Merseyside, Greater Manchester, Lancashire and Cheshire on tax structuring, developer VAT, SDLT and the long-view decisions that compound over the life of a portfolio.
This article is general information, not personal tax advice, and tax rules change. Your own position depends on facts we cannot see from here — please take advice before acting on anything above.