Does a higher property value always mean a higher lease extension premium?

Generally yes — property value is one of the core inputs in the lease extension valuation formula, and higher values produce higher premiums. However, the relationship is not purely linear. Years remaining on the lease, ground rent level, deferment rate and whether marriage value applies all affect the final premium. Two properties with the same value but different lease lengths can have very different premium levels.

Why is the average premium so much higher than the median for £600k+ properties?

The sample includes a small number of central London cases involving very short leases on very high-value properties, producing premiums above £1 million. These extreme outcomes pull the mean significantly above the median. The median (£50,268) is a more representative figure for most properties in this value range.

What was the most expensive lease extension in the dataset?

The largest tribunal-determined premium in the LeaseIntel dataset is £10,204,082, determined for a flat in Grosvenor Square, London W1K. This involved a very short unexpired term on an extremely high-value central London property. Cases of this scale are exceptional and account for only a handful of the 443 decisions in this analysis.

How does property value affect the calculation differently for properties with very short leases?

For leases below approximately 60 years, the marriage value component — the uplift in property value from extending the lease — becomes a major driver of the premium. On high-value properties, marriage value can represent a very large absolute sum, which is why £1m+ properties with short leases produce the most extreme premiums in the dataset. The standard calculation formula applies across all value bands, but its outputs are most dramatic at the intersection of high value and short term.

Are these figures relevant to all parts of England and Wales?

The dataset is predominantly London-based (approximately 75% of cases). Premium levels outside London are typically lower, reflecting lower freehold property values. The relationship between property value and premium applies nationally, but the absolute figures in this analysis should be treated with more caution for non-London properties. The underlying data for properties below £250,000 includes some non-London cases, while the £400,000+ bands are almost entirely London.

Lease Extension Cost by Property Value

Median premium — under £250k properties

£13,216

186 tribunal decisions

Median premium — £400k–£599k properties

£38,172

61 tribunal decisions

Median premium — £1m+ properties

£572,500

11 tribunal decisions

Why property value drives lease extension cost

Lease extension premiums are calculated using a valuation formula that takes the property's freehold value as a starting point. Higher-value properties generate larger reversionary values for freeholders, which directly increases the premium required to compensate them. This relationship is broadly linear up to around £600,000, beyond which the impact of very short leases and marriage value can produce extremely large premiums.

The tribunal data confirms this clearly. Across 443 decisions where both a tribunal-determined premium and a property value were recorded, median premiums rise consistently with property value — from £13,216 for properties worth under £250,000 to £572,500 for properties worth over £1 million.

Property value band	Decisions analysed	Median premium	Mean premium
Under £250,000	186	£13,216	£17,320
£250,000–£399,999	165	£27,160	£33,189
£400,000–£599,999	61	£38,172	£40,547
£600,000–£799,999	16	£50,268	£121,782
£1,000,000+	11	£572,500	£562,579

Source: LeaseIntel Tribunal Database

Sample: 443

Period: 2005–2025

The £600k+ premium effect

Properties above £600,000 show a striking divergence between median (£50,268) and mean (£121,782) premiums. This reflects a small number of very high-value cases involving very short unexpired terms combined with high property values — a combination that triggers both full marriage value and a large reversion calculation.

The £1 million+ band, while only 11 decisions, has a median of £572,500. Every case in this band involved a property in central London, and many had fewer than 20 years of lease remaining. These are not typical lease extension scenarios — they represent the most extreme end of the market.

What drives the premium within each band

Within any property value band, the single most important secondary factor is years remaining on the lease. A flat worth £350,000 with 85 years remaining will attract a substantially lower premium than an identical flat with 65 years remaining. The 80-year threshold is particularly significant: once a lease falls below 80 years, marriage value becomes payable, often adding 30–50% or more to the premium.

Ground rent level is a further variable. High ground rents increase the deferment value component of the calculation, adding to the overall premium. Tribunal decisions in the dataset show that ground rent type (fixed, reviewable, or RPI-linked) affects outcomes across all property value bands.

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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 443 tribunal decisions covering a range of property values. Your own premium depends on your property's specific value, the years remaining on your lease, ground rent terms and the valuation evidence presented. LeaseIntel compares your circumstances with similar tribunal decisions to provide a personalised benchmark.

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