Buying a flat with a short lease (under 80 years) — what to know

A short lease is the single biggest reason flats sell below market value, and the single biggest trap for first-time buyers chasing what looks like a bargain. If the lease has fewer than 80 years left, you are not really negotiating on the flat — you are negotiating on the lease.

The 80-year cliff

UK leasehold law has a quirk called marriage value. Once a lease drops below 80 years, the freeholder is legally entitled to half of the uplift in value created by extending it. In practice this can add £15,000-£30,000 to the cost of an extension overnight. A flat with 81 years left and an identical flat with 79 years left can have completely different price tags, and most sellers don't mention it.

If you're buying a flat with 82-85 years remaining, you should still extend soon. Lenders look at the lease term at the end of the mortgage, not the start. A 25-year mortgage on an 84-year lease leaves 59 years at the back end, which makes resale a problem.

Where lenders draw the line

Most high-street lenders refuse to lend on a lease with fewer than 70 years remaining, and several won't go below 85 at the point of application. Halifax, Nationwide and Santander all have published thresholds that a broker can confirm. If the lease is short, the buyer pool shrinks to cash buyers and specialist lenders, which is exactly why these flats sit on the market.

What an extension actually costs

You have a statutory right to a 90-year extension (added to the existing term) at peppercorn ground rent under the Leasehold Reform, Housing and Urban Development Act 1993. The premium — the lump sum paid to the freeholder — depends on the flat value, ground rent, and years remaining. As a rough guide:

Ballpark extension premiums

For a £300,000 flat in an average area: 95 years left costs around £4,000-£7,000. 81 years left costs around £8,000-£12,000. 78 years left jumps to £15,000-£25,000. 65 years left can be £30,000-£45,000+. Add £3,000-£5,000 for surveyor and solicitor fees on both sides, because under the 1993 Act you pay the freeholder's reasonable costs as well as your own.

Ground rent traps

Older leases sometimes contain ground rent doubling clauses (every 10, 15 or 25 years), or escalators tied to RPI. A doubling clause that takes ground rent to £8,000 a year by year 50 is a property nobody will buy or lend on. The Leasehold Reform (Ground Rent) Act 2022 abolished ground rent on new leases granted after June 2022, but it does not retroactively fix existing leases. Read the lease itself, not the estate agent's summary.

How to use the short lease in your offer

The cleanest play is: get a formal valuation of the extension premium from a specialist surveyor (a free desktop estimate from somewhere like LEASE or the Association of Leasehold Enfranchisement Practitioners is enough at offer stage). Then offer the asking price minus the full extension cost, including fees. Sellers of short-lease flats already know the maths; they just hope you don't. Many will accept.

Even better, ask the seller to serve a section 42 notice before exchange and assign the benefit to you on completion. That way you can extend immediately on day one rather than waiting two years to qualify. Your solicitor handles the wording.

Check the lease before you offer

Years remaining, ground rent terms, service charge history and any deeds of variation all show up on the title register. Pulling the official copy is £3 from HM Land Registry direct, or it's included in our paid reports along with a plain-English summary. See the title register check page for what shows up.