- The largest tribunal-determined premium in the dataset is £10.2 million — Grosvenor Square, London W1K.
- Twelve decisions exceed £1 million; all are in prime central London with very short unexpired terms.
- The ten largest cases account for approximately £24.6 million combined — under 1% of the 1,009 decisions analysed.
- The median premium across all decisions is £20,715 — less than 0.2% of the largest case, underlining how exceptional the top of the distribution is.
The ten largest tribunal-determined premiums
The ten largest premiums in the LeaseIntel dataset share a clear profile. All are located in prime central London — addresses in Grosvenor Square, Kensington, Belgravia, Cadogan Square and Knightsbridge. Most involve very short unexpired terms of under 25 years combined with property values in the millions. At this intersection of extreme scarcity (very little lease remaining) and extreme value, the premium calculation produces figures that bear little resemblance to a typical lease extension.
| Premium determined | Years remaining | Address | Region |
|---|---|---|---|
| £10,204,082 | N/A | Grosvenor Square, London W1K | London |
| £2,931,089 | 8.17 yrs | Kensington Court Gardens, London W8 | London |
| £2,575,000 | N/A | Egerton Gardens, London SW3 | London |
| £2,202,007 | 21.0 yrs | Upper Belgrave Street, London SW1 | London |
| £1,495,200 | 38.12 yrs | Sloane Street, London SW1 | London |
| £1,337,430 | 15.06 yrs | Cadogan Square, London SW1X | London |
| £1,313,686 | 12.13 yrs | Eaton Place, London SW1X | London |
| £1,203,870 | 12.98 yrs | Cadogan Gardens, London SW3 | London |
| £1,203,000 | N/A | Ennismore Gardens, London SW7 | London |
| £1,090,927 | 9.66 yrs | Connaught Court, London W2 | London |
What drives extreme premiums
Three factors combine to produce the largest premiums in the dataset. First, very short unexpired terms — most of the top ten cases involve fewer than 25 years remaining. At this stage, the marriage value component (the increase in property value that results from the extension) represents a very large absolute sum. Second, exceptionally high freehold values in prime central London, where comparable properties sell for millions. Third, in some cases, ground rents that are themselves substantial, adding to the deferment value component.
These cases are genuinely exceptional. The top ten account for a combined premium of approximately £24.6 million, but they represent fewer than 1% of the 1,009 decisions with determined premiums. The median premium across all decisions is £20,715 — less than 0.2% of the largest case.
Are these cases relevant to a typical leaseholder?
In most respects, no. The properties in the top ten list are among the most valuable residential addresses in the United Kingdom. The leaseholders involved faced costs that are simply not representative of the typical lease extension experience.
What these cases do illustrate — clearly and starkly — is the consequence of allowing a lease on a high-value property to fall to a very short term. The premium on a central London flat worth £3 million with 8 years remaining is of a different magnitude than the same flat with 85 years remaining. The exponential relationship between diminishing lease length and increasing premium applies at all price levels; these cases simply show it at its most extreme.
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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.
Read the full LeaseIntel methodology for dataset construction, variable definitions and validation checks.
Limitations & 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 represent the extreme end of the LeaseIntel dataset. The vast majority of lease extension premiums are far lower. Your own premium depends on your property's value, your specific lease length and the valuation evidence available. LeaseIntel compares your circumstances with similar tribunal decisions to provide a personalised benchmark.
Is My Lease Extension Quote Too High?Independent · Not a valuation or legal advice · Tribunal outcomes, not formula estimates