Lease length is one of the most important — and most misunderstood — factors in the value and mortgageability of a flat in England and Wales. Thousands of flat owners discover too late that their lease has fallen below the thresholds that trigger dramatically higher extension costs, or that lenders will not advance a mortgage at all. Understanding how lease extension works, what it costs, and when to act could save you tens of thousands of pounds.
Why Lease Length Matters: The Critical Thresholds
The 80-Year Threshold: Marriage Value
When a lease falls below 80 years remaining, a concept called marriage value kicks in. Marriage value is the increase in the property's value that results from the lease being extended — and crucially, the freeholder is legally entitled to 50% of this increase as part of the extension premium. Above 80 years, the freeholder gets nothing from marriage value. Below 80 years, the premium can increase dramatically. This is the most important reason to extend before you hit 80 years.
The 70–85 Year Lender Threshold
Most mainstream mortgage lenders will not lend on a property where the lease has fewer than 70–85 years remaining at the end of the mortgage term. Since mortgage terms are typically 25 years, this means lenders commonly require a lease of 95–105 years at the point of purchase to avoid complications. A flat with 75 years on the lease today will have only 50 years remaining at the end of a 25-year mortgage — well below most lenders' floors.
Below 60 Years: Serious Difficulty
Some lenders refuse outright to lend on leases below 60 years. At this stage, the property may also become effectively unmortgageable on the open market, severely restricting the pool of buyers to cash purchasers only.
Statutory vs Informal Extension
The Statutory Route: Leasehold Reform, Housing and Urban Development Act 1993
The Leasehold Reform, Housing and Urban Development Act 1993 (LRHUDA 1993) gives qualifying leaseholders the legal right to extend their lease by 90 years (added to the remaining unexpired term) at a peppercorn ground rent (effectively zero). This right exists regardless of the freeholder's wishes — they cannot refuse.
Qualifying criteria:
- You must have owned the flat for at least 2 years as a registered owner at HM Land Registry
- The lease must have been originally granted for more than 21 years
- The property must be a residential flat (not a house — houses are covered by separate legislation)
The Informal Route
You can also negotiate directly with the freeholder outside the statutory process at any time — even before you have owned for two years, or for terms that differ from the statutory formula. Advantages: quicker, potentially cheaper in professional fees, and the new lease terms can be more flexible. Disadvantages: you have no legal leverage — the freeholder can refuse or demand unreasonable terms — and the resulting lease may not follow the standard 90-year extension convention expected by lenders and future buyers.
The Formal Statutory Process: Step by Step
- Instruct a specialist leasehold solicitor — essential; this is technical legislation
- Commission a leasehold valuation surveyor to value the premium (the amount you must pay the freeholder)
- Serve a Section 42 Notice — the formal statutory notice specifying your proposed premium and starting the clock
- Freeholder serves a Counter-Notice within 2 months — accepting your terms, proposing different terms, or (rarely) asserting you do not qualify
- Negotiation period — typically 2–6 months of negotiation between valuers
- First-tier Tribunal (Property Chamber) — if no agreement is reached within 6 months of the counter-notice, either party can apply to the Tribunal to determine the premium
- New lease completed at Land Registry — process ends with registration of the new lease
How the Premium Is Calculated
The premium is calculated using a formula based on three components:
- Diminution in the value of the freeholder's interest — the present value of the ground rent income they lose when the lease is extended at peppercorn
- Marriage value — freeholder's 50% share of the increase in the flat's value resulting from the lease extension (only applies below 80 years)
- Ground rent capitalisation — the capitalised value of the lost ground rent
This is not a DIY exercise. Valuers use specialist leasehold valuation software and case law precedents (including Tribunal decisions) to arrive at a figure. The Savills Leasehold Calculator gives a rough indication.
Illustrative Premium Examples
| Years Remaining | Approximate Premium (£250k flat) |
|---|---|
| 90 years | £3,000 – £6,000 |
| 80 years | £7,000 – £12,000 |
| 75 years | £12,000 – £18,000 |
| 70 years | £16,000 – £25,000 |
| 65 years | £22,000 – £35,000 |
| 60 years | £28,000 – £50,000+ |
Figures are illustrative only. The actual premium depends on ground rent level, location, flat value and Tribunal decision precedents in your area. Always commission a surveyor.
Full Costs of a Lease Extension
| Cost Item | Typical Range |
|---|---|
| Premium payable to freeholder | £3,000 – £50,000+ |
| Your solicitor's fees | £1,500 – £3,000 |
| Your valuation surveyor | £500 – £1,500 |
| Freeholder's legal fees (you pay these) | £500 – £1,500 |
| Freeholder's surveyor fees (you pay these) | £500 – £1,000 |
| Land Registry registration fee | £20 – £910 (scale based on premium) |
| Stamp Duty Land Tax | Usually nil (leases on flats; premium below £250k) |
Under the statutory process, the building owner (leaseholder) pays both sides' reasonable professional costs. Budget for the freeholder's costs as well as your own.
Ground Rent Reform
The Leasehold Reform (Ground Rent) Act 2022 abolished ground rent for new residential long leases granted on or after 30 June 2022. New leases must now be at a peppercorn (zero). Existing leases with ground rent in excess of peppercorn are unaffected by this Act — but when you extend under the statutory route, the new 90 additional years runs at zero ground rent.
The Leasehold and Freehold Reform Act 2024 brought further changes, including measures to simplify the process and improve leaseholders' rights, though the detailed secondary legislation to fully implement the 2024 Act remains in progress as of mid-2026.
Enfranchisement: Buying the Freehold as a Group
If at least 50% of flats in your building wish to participate, qualifying leaseholders can collectively purchase the freehold under the LRHUDA 1993. This is called collective enfranchisement. The benefits: all leaseholders gain control of their building, can set reasonable service charges, grant themselves 999-year leases and eliminate ground rent entirely. The process mirrors the individual lease extension process: Section 13 notice → counter-notice → negotiation → Tribunal if no agreement.
Before Buying a Short-Lease Flat
If you are considering buying a flat with a short lease, our guide to buying a leasehold flat in the UK contains a full due diligence checklist. For a focused 7-point pre-offer guide — including the three critical lease numbers (70, 80 and 90 years), the EWS1 certificate for cladding, and Section 20 major works risks — see our buying a leasehold flat UK checklist. The core principles:
- Get a specialist leasehold solicitor to review the lease before you exchange
- Commission a leasehold valuation to understand the full extension cost
- Factor the full extension premium into your purchase price negotiation
- Check the freeholder's track record on service charges and lease renewals
- Confirm the property is mortgageable with your intended lender before you exchange
Also see our article on first-time buyer mistakes in the UK — lease length is one of the most common overlooked traps.
Key Takeaways
- Extend before you hit 80 years — marriage value makes it dramatically more expensive below that threshold.
- The statutory route gives you the right to a 90-year extension at peppercorn — the freeholder cannot refuse.
- You must own for 2 years before using the statutory route — buy right if buying a short-lease flat.
- Budget for both sides' costs — you pay the freeholder's reasonable legal and valuation fees.
- The 2024 Act changes are ongoing — the process is becoming simpler, but secondary legislation is still being enacted.
- Collective enfranchisement (buying the freehold with fellow leaseholders) remains the gold standard — it eliminates the problem permanently.
Related Guides
- Ground Rent Reform UK: What Leaseholders Need to Know — how the 2022 Act affects ground rent obligations on new and existing leases, and when lease extension eliminates a doubling clause
- Cladding and EWS1 Forms: What Buyers and Leaseholders Need to Know — fire safety obligations and qualifying leaseholder protections that run alongside lease length concerns