Lease extension: the 80-year rule explained

Lease extension rules matter because a leasehold home is owned for a fixed period, not forever. When the lease ends, ownership returns to the landlord. The key threshold in current law is 80 years: once a lease has 80 years or less left, the cost of extending it can rise significantly. This article explains what that means, the current statutory routes for flats and houses, what goes into the price, and which 2024 reforms are actually in force.

Leasehold basics

Leasehold means you own the property for a fixed period, and ownership returns to the landlord when the lease ends. The verified guidance also says most flats are leasehold. That is the basic reason lease length matters: the term is always running down.

The 80-year rule

The 80-year rule is the point at which extension costs can increase significantly. The verified legal sources say marriage value is taken as nil where the unexpired term exceeds 80 years, but it becomes part of the price at 80 years or less remaining. For flats, the premium includes the reduction in the landlord’s interest, the landlord’s share of marriage value and compensation; for houses, marriage value is shared 50/50 between landlord and tenant.

The statutory routes: flats vs houses

Different statutes apply to different property types. For houses, the statutory right to buy the freehold or an extended lease comes from the Leasehold Reform Act 1967. For flats, the Leasehold Reform, Housing and Urban Development Act 1993 applies, and a qualifying tenant has the right to a new lease on payment of a premium. Under current law, a valid flat claim starts with a formal section 42 notice, and disputes on the statutory valuation basis go to the appropriate tribunal. The current statutory extension terms are 90 years for flats and 50 years for houses.

What an extension costs

No single standard price is published; the sources set out what the statutory premium is based on for flats: the reduction in the landlord’s interest, the landlord’s share of marriage value and compensation, with marriage value nil above 80 years. Current law also says the tenant making a statutory claim pays the landlord’s reasonable costs of investigating the claim, valuing the flat and granting the new lease, but not tribunal proceedings costs. GOV.UK points leaseholders to the Leasehold Advisory Service lease extension calculator as the official guide to the cost of extending a flat lease.

The 2024 reforms: what is in force

The Leasehold and Freehold Reform Act 2024 received Royal Assent on 24 May 2024 and includes 990-year extensions for houses and flats, plus removal of the two-year ownership rule. But the verified position as of August 2026 is that the 990-year extension and the new valuation method are not yet in force, so the current statutory terms remain 90 years for flats and 50 years for houses, and removing marriage value is not yet law. One change is already in force: the two-year qualifying rule was removed on 31 January 2025, so new leaseholders no longer have to wait two years before buying or extending a lease.

Key facts

Source: GOV.UK - Leasehold property — Guidance checked August 2026

Source: GOV.UK - Extending, changing or ending a lease — Guidance checked August 2026

Source: legislation.gov.uk - Leasehold Reform Act 1967 s.1 — Guidance checked August 2026

Source: legislation.gov.uk - Leasehold Reform Act 1967 s.9 — Guidance checked August 2026