The relationship between lease length and property value is not a straight line. It is a curve - and it accelerates sharply once the lease drops below certain critical thresholds. Understanding this curve is essential for any London flat owner making decisions about selling, extending a lease, or simply understanding what their property is worth today.
The chart below is based on the relativity tables used by RICS-qualified surveyors and valuers across London. These are the same tables used in First-tier Tribunal cases and by major firms like Gerald Eve, Savills and Knight Frank when valuing leasehold interests.
Lease length vs property value
How to read the chart
The percentages show what proportion of its full (long-lease or freehold) value a flat typically retains at each lease length. So a flat worth £500,000 on a 999-year lease would be worth roughly:
- 99 years remaining: £490,000 (98%) - virtually no discount
- 80 years remaining: £465,000 (93%) - a £35,000 reduction
- 70 years remaining: £415,000 (83%) - £85,000 lost
- 60 years remaining: £360,000 (72%) - £140,000 lost
- 50 years remaining: £315,000 (63%) - £185,000 lost
- 40 years remaining: £250,000 (50%) - half the value gone
- 30 years remaining: £180,000 (36%) - nearly two-thirds lost
- 20 years remaining: £110,000 (22%) - over three-quarters of the value wiped out
These are stark figures. But they reflect the reality of what buyers will pay when they are taking on a depleting asset with a fixed expiry date.
Why the curve accelerates below 80 years
Look at the chart and you will see that the decline is gentle from 99 down to about 80 years - roughly 5% lost over nearly two decades. Then it steepens dramatically. From 80 to 60 years, you lose another 21%. From 60 to 40, another 22%. This acceleration is not random. It is driven by three reinforcing factors:
1. Mortgage availability collapses
Most high street lenders require a minimum of 70-85 years remaining at the end of the mortgage term. For a standard 25-year mortgage, that means the lease needs to be 95-110 years at the start. Once the lease drops below about 85 years, buyers start losing access to mainstream mortgages. Below 60 years, the flat is effectively unmortgageable. For the full picture, see our guide on short leases and mortgages.
Fewer mortgages means fewer buyers, which means less competition for your flat, which means lower prices. It is simple supply and demand.
2. Marriage value kicks in at 80 years
Under current legislation (the Leasehold Reform, Housing and Urban Development Act 1993), when a lease drops below 80 years, the freeholder becomes entitled to claim marriage value when you extend. Marriage value is 50% of the increase in the flat's value created by the extension. This can add tens of thousands of pounds to the extension premium.
Buyers factor this in. They know that to make the flat fully marketable, they will need to extend the lease, and the cost of doing so below 80 years is significantly higher. So they reduce their offer accordingly.
3. The "clock is ticking" psychology
As the lease gets shorter, urgency increases. A flat with 30 years remaining is unmortgageable through mainstream lenders, extremely difficult to sell on the open market, and losing value rapidly. The owner has limited time to either extend the lease, sell, or watch the value erode further each year. Buyers (particularly investors) know this and negotiate hard, expecting sellers to accept lower prices because their alternatives are limited.
What the chart means in real money
To make this concrete, here are three London scenarios based on the chart percentages:
A one-bedroom flat in Battersea
Long-lease value: £350,000
- With 75 years: worth roughly £308,000 (88%). Lost: £42,000
- With 60 years: worth roughly £252,000 (72%). Lost: £98,000
- With 45 years: worth roughly £199,500 (57%). Lost: £150,500
A two-bedroom flat in Hackney
Long-lease value: £500,000
- With 75 years: worth roughly £440,000 (88%). Lost: £60,000
- With 60 years: worth roughly £360,000 (72%). Lost: £140,000
- With 45 years: worth roughly £285,000 (57%). Lost: £215,000
A three-bedroom flat in Kensington
Long-lease value: £1,200,000
- With 75 years: worth roughly £1,056,000 (88%). Lost: £144,000
- With 60 years: worth roughly £864,000 (72%). Lost: £336,000
- With 45 years: worth roughly £684,000 (57%). Lost: £516,000
The higher the flat's underlying value, the more money is at stake with each passing year.
The cost of waiting
One of the most important things the chart illustrates is the cost of inaction. Every year you wait, the lease gets one year shorter and the flat loses value. This loss is not theoretical - it shows up in real offers from real buyers.
Take the Hackney example above. Between 75 and 60 years, the flat loses roughly £80,000 in value - that is about £5,300 per year. But the loss per year accelerates as the lease shortens further. Between 60 and 45 years, it loses roughly £75,000 - about £5,000 per year. And once you factor in the increasing cost of a lease extension as the lease shortens, the true annual cost of waiting is higher still.
This is why property professionals consistently advise acting sooner rather than later. Whether you extend the lease or buy the freehold, or sell the flat, the financial case for doing it now rather than next year is usually clear.
Important caveats
The chart shows typical relativity values. Your flat's actual value depends on several additional factors:
- Location matters. Flats in prime Central London (Mayfair, Knightsbridge, Chelsea) tend to hold their value slightly better at shorter lease lengths because there is stronger cash buyer demand. Flats in outer boroughs where most buyers need mortgages suffer more
- Ground rent terms. A flat with a low, fixed ground rent of £100 per year will hold its value better than one with ground rent that doubles every 10 years. Some ground rent terms are so onerous that they reduce the flat's value over and above the lease length effect. See what is a short lease for more on how ground rents interact with lease length
- Freeholder cooperation. If the freeholder is known to be reasonable and willing to negotiate extensions at fair prices, the flat's value is better supported. An uncooperative or absentee freeholder adds risk and cost, which reduces what buyers will pay
- Building type and condition. A well-maintained purpose-built block holds value better than a converted house with shared services and potential structural issues
- Multiple relativity tables exist. Different graphs (Gerald Eve, Savills, Beckett and Kay, the Sportelli rate) produce slightly different percentages. The figures above are broadly representative, but your surveyor may use a different table depending on the circumstances
What should you do?
If your lease is above 90 years, there is no urgency - but it is worth keeping an eye on the numbers. If it is between 80 and 90 years, start planning. Below 80 years, the financial case for acting quickly is strong.
Your options are:
- Extend the lease to restore the flat's full value. Use our lease extension calculator to estimate the cost
- Sell the flat to a specialist buyer who can handle the short lease. We buy flats at any lease length and complete in as little as 2-4 weeks
- Buy the freehold with your neighbours to take full control. See our freehold vs lease extension guide for a comparison
To find out what your specific flat is worth today, request a free valuation. We will give you a figure based on your flat's actual details - its location, condition, ground rent terms and lease length - not just a generic chart. Or call us on 020 7183 3022 and we will talk it through with you.