Short-lease leasehold properties - flats with unexpired terms of 80 years or below - are a consistent feature of the UK investment and auction market. They are frequently priced at a discount to reflect the lease length, and they offer investors a genuine opportunity to buy at below-market value and then extend the lease, recovering or creating significant equity in the process. But the lease extension process has its own complexity, its own costs and its own timeline, and it needs to be understood before committing to a short-lease acquisition.

This guide explains how the lease extension process works, what it costs, when the statutory route is available, what the Leasehold and Freehold Reform Act 2024 has actually brought into force - which is considerably less than the coverage of that Act suggested - and how investors should factor lease extension into their due diligence and investment modelling.

Why Lease Length Matters

A leasehold property is only owned for the duration of the lease. As the remaining term decreases, several consequences flow:

  • Mortgageability - most lenders require a minimum unexpired term at the point of application. Many lenders will not lend below 70 to 85 years depending on the lender and product. Properties with very short leases may be effectively unmortgageable.
  • Value - the market discounts short-lease properties significantly. The discount accelerates as the lease shortens and particularly below 80 years.
  • Extension cost - the premium payable to extend the lease increases as the lease gets shorter, and above 80 years the statutory formula excludes marriage value (which adds materially to the cost below 80 years).
  • Resale pool - a property with a short lease can only be sold to a cash buyer or to someone willing and able to extend. This reduces the buyer pool and constrains exit options.

For investors, the core opportunity is to buy at the short-lease discount, extend the lease, and then hold, refinance or sell at the post-extension value. The commercial viability of this strategy depends on the relationship between the acquisition price, the extension cost and the post-extension market value.

The Statutory Route: Section 42 Notice

Qualifying leaseholders of flats in England and Wales have a statutory right under the Leasehold Reform, Housing and Urban Development Act 1993 to extend their lease by 90 years on top of the unexpired term, at a peppercorn (zero) ground rent, subject to paying a premium to the freeholder. The claim is made by serving what is generally called a Section 42 notice.

The two-year ownership requirement has been abolished. It was removed by the Leasehold and Freehold Reform Act 2024 with effect from 31 January 2025. A buyer no longer has to wait two years before claiming - the right is available as soon as they are the registered owner of the flat.

That is a material improvement for short-lease investors, and it is worth being precise about what it does and does not do.

What it does: it removes the old holding period, during which the lease shortened and the premium rose. An investor acquiring a short-lease flat can now begin the statutory process immediately rather than waiting two years or negotiating an informal extension in the meantime.

What it does not do: it does not make the right available on completion day. The claim depends on being the registered owner, and registration of a leasehold transfer is not instant. Where the unexpired term is close to 80 years, a registration delay of several months can be the difference between a claim valued above the threshold and one valued below it - which is a question of cost, not administration.

It also does not make a notice already served by the seller worthless. That point is dealt with separately below.

Where a Notice Has Already Been Served

Before 31 January 2025 the standard workaround for a buyer who could not yet claim was for the seller to serve a Section 42 notice shortly before completion and assign the benefit of it to the buyer under the contract. That workaround is no longer necessary. It has not stopped being valuable.

The premium is assessed by reference to the valuation date, which is the date the notice was served. Where a seller served while the unexpired term was still above 80 years, the notice has fixed the valuation on a basis that excludes marriage value. On a lease now sitting below the threshold, the benefit of that notice can be worth a substantial sum - and it passes to the buyer only if the contract assigns it.

For an auction lot this produces two questions rather than one. Not only how long the lease is, but whether a notice has already been served and whether the special conditions assign the benefit of it to the buyer. The lease should also be checked for any restriction on the assignment of a pending statutory claim.

How the Lease Extension Premium Is Calculated

The statutory premium for a lease extension is calculated using a formula that takes into account:

  • The diminution in the value of the freeholder’s interest arising from the extension - the longer the remaining lease, the less valuable the freeholder’s reversion.
  • The loss of ground rent - the capitalised value of the ground rent payments the freeholder would have received over the remaining term.
  • Marriage value - where the unexpired term is below 80 years, the leaseholder must pay 50% of the marriage value (the increase in the combined value of the freehold and leasehold that results from the extension). This is the most significant cost driver for leases below 80 years.

A lease with, say, 75 years remaining will attract a materially higher premium than the same property with 85 years remaining, primarily because of the marriage value element. The premium is not a fixed amount but is the subject of negotiation between the leaseholder’s and freeholder’s surveyors, with ultimate reference to the First-tier Tribunal (Property Chamber) if agreement cannot be reached.

Investors should obtain a preliminary valuation from a specialist leasehold valuation surveyor before acquisition. The surveyor can provide an indicative premium range based on the current lease length, the property value and the ground rent terms. This figure needs to be built into the acquisition budget alongside the purchase price and legal costs.

The Leasehold and Freehold Reform Act 2024: What Is Actually in Force

The Leasehold and Freehold Reform Act 2024 received Royal Assent in May 2024 and was widely reported as having reformed lease extension valuation. Most of that valuation reform is in the Act but has not been commenced, and the distinction is commercially significant: an investor who prices a short-lease acquisition on the reformed basis is pricing a law that is not yet in effect.

The position as at October 2026:

  • Abolition of the two-year ownership requirement - in force. Commenced 31 January 2025, as set out above.
  • Abolition of marriage value - not in force. The Act removes marriage value from the statutory premium, but the provision has not been commenced. Marriage value remains payable in full where the unexpired term is below 80 years, and remains the largest single component of the premium on those claims.
  • The 990-year extension term - not in force. The statutory extension remains 90 years on top of the unexpired term.
  • The standardised valuation method - not in force. The Act provides for prescribed capitalisation and deferment rates, and those rates have not yet been set.

Freeholders challenged the valuation provisions on human rights grounds. The High Court dismissed the claims in October 2025, and permission to appeal was granted in April 2026. The commencement timetable for the valuation reforms remains unconfirmed.

The practical conclusion is straightforward. Model the acquisition on the law as it stands, with marriage value included wherever the unexpired term is below 80 years. Treat the reforms as upside if and when they commence, rather than as a basis for a bid. And verify the position at the time of the transaction, because this is an area that is still moving.

Informal Extension vs Statutory Route

In addition to the statutory route, it is possible to negotiate an informal lease extension directly with the freeholder outside the statutory process. The advantage of the informal route is speed and flexibility - there is no prescribed procedure and no statutory timetable, and the parties can agree terms that differ from the statutory formula.

The disadvantage is that the investor has no legal entitlement to the extension and the freeholder can negotiate from a position of greater strength, potentially demanding a higher premium than the statutory formula would produce. Informal extensions may also result in leases that retain a reviewable ground rent, which can create problems for mortgage lenders and future buyers.

The general principle is that the statutory route, while more procedurally involved, produces greater certainty of outcome and greater legal protection. For investors whose strategy depends on the extension being achievable at a defined cost, the statutory route provides a more reliable framework - and now that the two-year requirement has gone, it is available from the start of ownership.

Finance Implications for Short-Lease Acquisitions

Most mainstream mortgage lenders will not lend on properties with very short leases. For investors acquiring short-lease property with the intention of extending, the acquisition is therefore often made with cash or bridging finance, with a plan to refinance onto a standard buy-to-let mortgage once the lease has been extended to a lender-acceptable length.

This finance strategy has its own risk considerations: the bridging cost during the extension period, the timeline of the extension process (typically six to eighteen months on the statutory route), and the certainty that the post-extension refinance will be available at the anticipated terms. These should all be modelled before acquisition.

For any short-lease acquisition, the due diligence checklist should include:

  • The precise unexpired term - calculated from the date of grant to the expiry date, not from a description in the pack.
  • The ground rent provisions - whether they affect the premium calculation or lender acceptability.
  • Whether any prior extension notice has been served by the seller - its date, which fixes the valuation date, its current status, and whether the special conditions assign the benefit of it to the buyer.
  • Any restrictions in the lease on assignment of a pending statutory claim.
  • The likely registration timetable, where the unexpired term is close to 80 years and a delay in registering would carry the claim below the threshold.
  • Whether the freeholder is identifiable and cooperative - an absent or uncooperative freeholder will require a different approach.
  • The title class - good leasehold title may require additional steps in the extension process.

Bidq reviews short-lease legal packs, identifies extension rights and costs, and provides the investor-focused assessment you need before bidding. Learn more about Bidq’s pre-auction due diligence review.