How much more expensive does a lease extension get each year I wait?

The tribunal data does not provide a single annual cost figure because the increase depends on the current lease length and property value. However, the data shows that premiums roughly double between the 80–89 year band and the 70–79 year band, and double again between 70–79 years and 60–69 years. For a property worth £400,000 with 78 years remaining, delaying by five years could add £10,000–£20,000 to the premium. An enfranchisement valuer can model the specific cost of waiting for your property.

What happens to my premium when my lease falls below 80 years?

When a lease falls below 80 years, marriage value becomes payable. Marriage value is 50% of the increase in property value that results from the lease extension, and it is paid to the freeholder as part of the premium. This creates a step-change in cost that is clearly visible in the tribunal data: leases just below 80 years show median premiums approximately 79% higher than leases just above 80 years. Acting before the lease falls below 80 years is one of the most important decisions a leaseholder can make.

Can I serve notice before I'm ready to complete the extension?

Yes. Serving a Section 42 notice (the formal claim notice) under the Leasehold Reform, Housing and Urban Development Act 1993 locks in the valuation date for calculating the premium. If your lease is approaching 80 years, serving notice while above 80 years — even if completion takes longer — protects you from the marriage value step-change. This is a commonly used strategy and should be discussed with a specialist solicitor.

Does the cost of waiting also apply to informal extensions?

Yes, but in a different way. Informal extensions negotiated directly with the freeholder are not governed by the statutory formula — the freeholder can charge what the market will accept. As a lease shortens, the leaseholder's negotiating position weakens and informal offers typically become less favourable. The LeaseIntel dataset focuses on tribunal-determined premiums under the statutory route.

Why have median premiums risen so much since 2015?

The tribunal data shows median determinations rising from £17,133 in 2015 to £36,750 by 2025. This primarily reflects rising London property values, which increase the freehold reversion and therefore the premium calculation. It also reflects a gradual shift in the composition of tribunal cases toward shorter-lease, higher-value properties as leaseholders with longer leases have less immediate urgency. The data should be treated as directional rather than predictive.

The Cost of Waiting to Extend Your Lease

Median premium — 80–89 years remaining

£7,046

30 tribunal decisions

Median premium — 70–79 years remaining

£12,622

103 tribunal decisions — 79% higher

Median premium — 60–69 years remaining

£23,463

213 tribunal decisions — 86% higher again

How the cost rises as the lease shortens

The tribunal data tells a clear story: premiums rise at an accelerating rate as lease length falls. The increase is not linear — it compounds. Moving from 85 years to 75 years typically costs far more in additional premium than moving from 95 years to 85 years, and moving from 75 years to 65 years costs more again.

The table below shows median premiums across lease length bands from the LeaseIntel dataset. The jump from the 80–89 year band to the 70–79 year band (£7,046 to £12,622) represents a 79% increase in the typical premium — and this is before the most expensive territory, below 60 years.

Years remaining	Decisions analysed	Median premium	vs next band up
80–89 years	30	£7,046	—
70–79 years	103	£12,622	+79%
60–69 years	213	£23,463	+86%
50–59 years	136	£41,384	+76%
40–49 years	41	£47,300	+14%
Under 40 years	63	£236,988	+401%

Source: LeaseIntel Tribunal Database

Sample: 595

Period: 2005–2025

The 80-year threshold: where the real cost of waiting hits

The most consequential moment in a lease extension timeline is crossing the 80-year threshold. Under current legislation, marriage value — the uplift in property value that results from extending the lease — is only payable when the lease falls below 80 years. This creates a step-change in premiums that is visible in the tribunal data.

Leases in the 80–89 year band show a median premium of £7,046. Leases in the 70–79 year band show a median of £12,622 — a difference of £5,576. For a property worth £400,000, the real-world cost of crossing this threshold is typically even larger, as marriage value on higher-value properties represents a larger absolute sum.

The implication is direct: a leaseholder with 82 years remaining who delays extending by three years — crossing below 80 years — faces a premium increase that, in the tribunal data, represents approximately 79% more than if they had acted above the threshold. In cash terms on a typical London flat, this is often £8,000–£20,000 or more.

The rising trend in premiums over time

Beyond the lease-length effect, the tribunal data also shows a rising trend in median premiums over time. The median determination has risen from £17,133 in 2015 to £36,750 by 2025 — more than doubling over ten years. This reflects both rising London property values and the gradual composition of the dataset shifting toward shorter-lease, higher-value cases as leaseholders with longer leases have less urgency to go to tribunal.

The practical implication: a leaseholder who defers extending is not only allowing their lease to shorten — they are also extending into a market where the underlying freehold values, and therefore the premiums, are rising. The combined effect of lease shortening and market appreciation makes delay more costly than either factor alone.

Year	Decisions	Median premium determined
2015	70	£17,133
2016	48	£24,188
2017	79	£24,591
2018	98	£24,499
2019	96	£28,320
2020	34	£26,193
2021	58	£28,820
2022	51	£33,034
2023	27	£34,950
2025	21	£36,750

Source: LeaseIntel Tribunal Database

Sample: 595

Period: 2005–2025

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Frequently asked questions

Methodology

LeaseIntel analyses published First-tier Tribunal (Property Chamber) decisions on lease extension premiums. Each decision is parsed into a structured record covering unexpired term at the valuation date, property value, ground rent profile, deferment and capitalisation rates, marriage value treatment and the final premium determined.

Analyses only include decisions containing the specific lease-term and valuation data required for that study.
Cases are grouped by unexpired term at the valuation date (not the date of the decision).
Sample sizes vary between analyses because not every decision records every variable.
Small sample groups are flagged with a confidence indicator and interpreted cautiously.
Where decisions span multiple flats or hearings, each lease is treated as a separate observation.

Caveats

Tribunal decisions represent disputed cases rather than the entire market.
Not all decisions contain every data field.
Sample sizes vary by analysis.
Small sample groups should be interpreted cautiously.

Benchmark your quote

These figures are based on 595 tribunal decisions showing how premiums change with lease length. Your own premium depends on your specific lease length, property value, ground rent terms and the valuation date. LeaseIntel compares your circumstances with similar tribunal decisions to provide a personalised benchmark — including the estimated cost of waiting.

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Independent · Not a valuation or legal advice · Tribunal outcomes, not formula estimates