Illustrative Cost Impact of Crossing the 80-Year Cliff Edge (£300,000 Flat)
To understand why property lawyers call 80 years the 'cliff edge', consider a typical leasehold flat worth £300,000 (long lease/relativity 100% value) with a £200/year ground rent, using the statutory 5% Sportelli deferment rate:
| Remaining Lease Length | Estimated Flat Relativity (% of Full Value) | Marriage Value Payable (50% Share) | Total Estimated Extension Premium | Mortgageability Status |
|---|---|---|---|---|
| 85 Years Remaining | ~97% (Statutory No-Marriage-Value Zone) | £0 (Exempt under Schedule 13) | £4,500 – £6,000 | 100% Mortgageable with all UK lenders |
| 80.5 Years Remaining | ~95% (Final Safety Window) | £0 (Exempt if s.42 Notice served now) | £5,500 – £7,200 | 100% Mortgageable — Extend immediately! |
| 79 Years Remaining | ~93.5% (Marriage Value Triggered) | +£6,500 – £8,500 Marriage Value jump | £13,000 – £16,500 | Caution — Premium more than doubles overnight |
| 72 Years Remaining | ~89.0% (Short Lease Penalty) | +£12,000 – £15,000 Marriage Value | £21,000 – £26,000 | Restricted — Many high-street lenders refuse |
| 60 Years Remaining | ~80.0% (Cash-Buyer / Specialist Territory) | +£24,000 – £28,000 Marriage Value | £38,000 – £46,000 | Unmortgageable on standard retail products |
What Exactly Is 'Marriage Value' in Plain English?
A flat with a short 70-year lease is worth significantly less on the open market than the exact same flat with a 160-year or 990-year lease. When the leaseholder extends the lease, the 'marriage' of the short lease with the new long extension creates an immediate jump in the property's capital value.
Under Schedule 13 of the Leasehold Reform, Housing and Urban Development Act 1993, whenever a lease has fewer than 80 years left at the valuation date, Parliament requires that capital uplift ('marriage value') to be split 50/50 between the leaseholder and the freeholder. The Leasehold and Freehold Reform Act 2024 includes provisions in Schedule 4 to abolish marriage value completely once the secondary valuation rate regulations are brought into force.
Under Section 42 and Schedule 13 of the 1993 Act, the 'valuation date' is fixed on the exact day the freeholder receives your valid Section 42 Tenant's Notice. Even if your lease has only 80 years and 3 days left when the postman delivers the Section 42 Notice, your marriage value is locked at £0 forever for that claim—even if the actual extension deed takes another 10 months to complete!
How to Buy or Sell a Flat Sitting Between 75 and 82 Years
If you are buying a leasehold flat that has between 75 and 82 years remaining, you and your conveyancing solicitor have two main transactional strategies:
1. Seller Serves Section 42 Notice Between Exchange and Completion (Section 43(3) Assignment): Particularly critical if the lease is at 80.1 to 80.5 years! Because HM Land Registry currently takes several months to register a new buyer's title (the 'registration gap'), waiting until after completion to serve your own notice could see the lease slip below 80.0 years while waiting for Land Registry. Having the seller serve the Section 42 Notice and assign the benefit to you on completion locks in the valuation date immediately.
2. Immediate Post-Registration Notice (Under the 31 January 2025 Reform): If the lease has 81.5+ years remaining (or is already below 80 years), you no longer have to wait 2 years after purchase—as soon as your solicitor expedited your Land Registry registration, you can serve your own Section 42 Notice.
Checklist for Flat Buyers & Owners Approaching 80 Years
Follow these five steps to protect your equity: