Most leaseholders discover their lease is a problem at the worst possible moment — when a buyer pulls out, a lender queries the term, or a valuation comes back lower than expected. By then the options have narrowed and the cost has usually risen.

A lease extension adds years to the remaining term of a leasehold property, normally in return for a payment to the freeholder called a premium. The reason it matters is that a lease is a wasting asset. Every year the unexpired term shortens, the property's value falls a little further and the eventual cost of putting it right goes up.

For anyone dealing with a lease extension London brings particular complications. Values are high, so premiums are high. Comparable evidence varies street by street. And a large proportion of the capital's housing stock is leasehold flats, many with leases granted decades ago that are now approaching the point where they become difficult to sell or mortgage.

This guide explains how the process actually works, who does what, what it costs, and what to watch for.

What Is a Lease Extension?

Owning a leasehold flat means owning the right to occupy it for a fixed period. That period runs down. The freeholder owns the building and the land, and the right to possession once the lease expires.

A lease extension replaces that fixed period with a longer one. In practice, the existing lease is usually surrendered and a new lease granted on revised terms, rather than the original document being amended.

Two things follow from this:

• Value. A flat with 150 years remaining trades much like a freehold. A flat with 70 years remaining does not. The gap widens as the term shortens.
• Mortgageability. Most lenders set minimum lease length requirements, often expressed as a number of years remaining at the end of the mortgage term. Fall below that and the pool of buyers who can obtain finance shrinks sharply.

A qualifying leaseholder generally has a legal right to extend, so this is not a matter of asking the freeholder for a favour. It is a right, exercised through a defined procedure, at a price.

Why Extend Your Lease?

• Protect the value of your property. The premium is a cost, but a short lease is a permanent drag on value.
• Keep it saleable. Buyers and their solicitors look at lease length early. A short lease narrows your market.
• Satisfy lenders. Mortgage availability tightens as the term falls, affecting both you and any buyer.
• Avoid problems mid-sale. Discovering a lease issue during a transaction is expensive and can lose the sale.
• Plan ahead. Extending while the lease is comfortably long is considerably cheaper than doing it once it is short.

The timing point is the one most often missed. Waiting rarely improves your position.

How Does the Lease Extension Process Work?

1. Check the existing lease. Find the term commencement date and calculate the unexpired term precisely. Note the ground rent and how it is reviewed.

2. Establish eligibility and objectives. Confirm you qualify and decide what you want — the cheapest route, the fastest, or the cleanest lease.

3. Get professional advice. Usually a valuer and a solicitor. Speak to both before serving anything.

4. Instruct a RICS-qualified valuer. They assess the premium and provide the figure your claim will be built on.

5. Calculate the likely premium. Your valuer gives a realistic range, not a single number, because the outcome depends on negotiation.

6. Agree the strategy. Statutory or informal, opening figure, and what you will settle at.

7. Serve notice. On the statutory route for a flat, your solicitor serves a Section 42 notice setting out your proposed premium. The freeholder responds with a counter-notice.

8. Negotiate. Usually valuer to valuer. If terms cannot be agreed, either side can apply to the First-tier Tribunal (Property Chamber), though most cases settle.

9. Complete the legal work. Solicitors agree the new lease and complete.

10. Register. The new lease is registered at HM Land Registry.

What Is a RICS Lease Extension Valuation?

RICS is the Royal Institution of Chartered Surveyors. A valuation prepared by a RICS Registered Valuer follows professional standards, which is what allows it to be tested in negotiation or before a tribunal.

A RICS lease extension London valuation typically assesses:

• The unexpired lease term, calculated precisely
• The flat's value now, and its value with an extended lease
• The ground rent and its capitalised value
• The freeholder's reversionary interest
• Local comparable evidence
• Marriage value, where the current rules require it
• Any unusual lease terms affecting value

The output is a reasoned opinion with the assumptions set out, not just a figure. That reasoning is what gives it weight when the freeholder's valuer proposes something different.

A qualification alone guarantees nothing. Enfranchisement valuation is a specialism within surveying, and experience of the specific London submarket matters. Ask about both.

Lease Extension in London: What Should Leaseholders Consider?

London is different in ways that affect the numbers directly.

Values are higher, so premiums are higher. The same lease length on the same flat type produces very different figures in Camden and in Croydon.

Comparable evidence is hyper-local. Values can shift meaningfully between neighbouring streets or between floors of the same block. A valuer working from borough-wide averages will not produce a defensible figure.

The stock is varied. Purpose-built mansion blocks, converted Victorian houses, ex-local authority flats and new-build apartments each behave differently, with different lease structures and ground rent provisions.

Freeholders vary too. Some are large professional estates with in-house surveyors who negotiate these claims constantly. Going in without equivalent expertise puts you at a disadvantage.

The practical conclusion is to work with people who know the specific market, not just the subject.

Statutory vs Informal Lease Extension

The statutory route uses your legal right. For a flat, that currently means 90 additional years at a peppercorn ground rent under the Leasehold Reform, Housing and Urban Development Act 1993, started by a Section 42 notice. The procedure is prescribed, the timescales are fixed, and if you cannot agree the premium the tribunal decides. You pay the freeholder's reasonable valuation and legal costs.

The informal route is a private negotiation. There is no notice, no prescribed procedure and no tribunal backstop. It can be quicker and cheaper in fees, and some freeholders prefer it.

The risks of going informal are worth understanding:

• No tribunal to fall back on if talks collapse
• The freeholder may propose fewer additional years
• Lease terms can change, sometimes unhelpfully
• Ground rent treatment is negotiated rather than fixed at a peppercorn
• A resulting lease that lenders dislike can cause problems on sale

Informal deals can work well, particularly where the freeholder is reasonable and the lease is long. But take advice on the offer before accepting it, and compare it against what the statutory route would deliver.

How Much Does a Lease Extension Cost?

There is no standard price, and any figure quoted without sight of your lease should be treated with caution.

Costs typically include:

• The premium — much the largest element
• Your valuer's fee
• Your solicitor's fee
• The freeholder's reasonable valuation and legal costs, payable by you on the statutory route
• Land Registry fees
• Stamp Duty Land Tax, where the premium exceeds the relevant threshold
• Tribunal costs, if the matter is not settled

The premium itself is driven by the property's value, the unexpired term, the ground rent and its review provisions, and the valuation assumptions applied. Because those inputs interact, lease extension costs London-wide vary far more than people expect.

Online calculators give an indication at best. They cannot read your lease or weigh local evidence, and a figure produced without either is not something to budget against.

Why the 80-Year Lease Threshold Matters

Under the current framework, once the unexpired term falls below 80 years, marriage value enters the calculation.

Marriage value is the uplift in combined value created by the extension itself. Below 80 years, the legislation requires half of it to be paid to the freeholder as part of the premium. The effect is a step up in cost as the lease crosses that line — which is why advisers push leaseholders to act before it happens.

The Leasehold and Freehold Reform Act 2024 provides for abolishing marriage value. That provision is not in force. As at September 2026 no commencement order has been made, and a claim served today is valued under the existing rules with marriage value included.

This is worth stating clearly because a good deal of published commentary says otherwise. Legislation being passed and legislation being in force are different things. Check the current position, or ask an adviser who will.

What Does a Lease Extension Solicitor Do?

Lease extension solicitors handle the legal side, which runs in parallel with the valuation rather than after it.

• Reviewing the lease and confirming you qualify
• Advising on the route — statutory or informal
• Serving the Section 42 notice correctly, with the right content and to the right party
• Handling the counter-notice and any technical issues arising
• Dealing with the freeholder's solicitors
• Negotiating the terms of the new lease, not just the price
• Completing and registering at HM Land Registry

The notice stage is where a specialist earns their fee. A defective notice can invalidate a claim, and there are situations — an absent freeholder, an intermediate landlord, a missed deadline — where general conveyancing experience is not enough. A lease extension solicitor who does this work regularly will spot those early.

Do You Need a Lease Extension Company?

A lease extension company is a specialist advisory service that coordinates the process. Some employ valuers, some work with panels of surveyors and solicitors, and some act as project managers keeping the parts moving.

The distinction worth understanding is that these are three different functions:

A company can be genuinely useful if you would rather not manage two sets of professionals. But it does not replace either. If a service offers to handle everything, ask specifically who is carrying out the valuation, whether they are RICS-registered, and who is doing the legal work.

Common Mistakes to Avoid

• Waiting. The cost rises as the term falls, particularly near 80 years.
• Accepting the first figure. A freeholder's opening premium is a negotiating position.
• Choosing on price alone. The cheapest valuer may cost you far more in the premium.
• Not reading the lease. Ground rent review clauses in particular affect the numbers.
• Missing deadlines. Statutory timescales are strict, and missing one can end a claim.
• Relying on outdated information. Much published content about leasehold reform is wrong about what is in force.
• Forgetting the freeholder's costs. On the statutory route you pay their reasonable fees too.
• Running valuation and legal work separately. They should be coordinated from the start.

How Long Does a Lease Extension Take?

Timescales vary considerably, and no honest adviser will promise a date.

• Initial advice — days to a couple of weeks
• Valuation — typically a few weeks, including the inspection
• Notice and legal preparation — a few weeks
• Counter-notice period — fixed by statute, generally a minimum of two months
• Negotiation — weeks to months, depending on the parties
• Documentation and completion — several weeks
• Registration — HM Land Registry timescales vary and can be lengthy

A straightforward statutory claim commonly takes several months from start to completion. Tribunal involvement extends that. If you are extending ahead of a sale, start earlier than you think you need to.

How to Choose the Right Lease Extension Professionals in London

• Relevant experience — specifically enfranchisement, not general practice
• RICS registration for anyone doing valuation work
• London market knowledge, ideally of your borough
• Transparent fees set out in writing before you commit
• Clear communication — you should understand the advice you are given
• Reputation — reviews, referrals, tribunal experience
• Professional indemnity insurance
• Current knowledge of what is actually in force, not what has been announced

That last point is a useful test. Ask what the reform position is. Anyone who tells you marriage value has been abolished is not following it closely enough.

Frequently Asked Questions

What is a lease extension? It is the process of adding years to the remaining term of a leasehold property, usually in exchange for a premium paid to the freeholder. In most cases the existing lease is surrendered and a new one granted on revised terms rather than the original being amended.

How does the lease extension process work? You check the lease, confirm eligibility, obtain a valuation, then either serve a statutory notice or negotiate informally. The premium is negotiated, the legal documentation completed, and the new lease registered at HM Land Registry. Valuation and legal work run in parallel.

How much does a lease extension cost in London? There is no standard figure. The premium depends on your flat's value, the unexpired term and the ground rent, and London premiums vary widely by borough. Budget also for valuation fees, legal fees, the freeholder's reasonable costs, registration and potentially Stamp Duty Land Tax.

Is an RICS valuation necessary for a lease extension? It is not a legal requirement, but proceeding without one means negotiating against the freeholder's valuer with nothing evidenced to test their figure against. For most leaseholders the fee is small relative to the premium at stake.

What does a lease extension solicitor do? They review the lease, advise on the route, serve the Section 42 notice, handle the counter-notice, deal with the freeholder's solicitors, negotiate the terms of the new lease, complete the transaction and register it. The notice stage is where specialist experience matters most.

How long does a lease extension take? A straightforward statutory claim commonly takes several months, driven by notice periods, negotiation, conveyancing and registration. Tribunal proceedings extend it. Informal extensions can be quicker but have no fixed timetable.

What happens if my lease has less than 80 years remaining? Under the current rules, marriage value enters the premium calculation and half is payable to the freeholder, which increases the cost. The 2024 Act provides for abolishing marriage value, but that provision is not yet in force.

Can I negotiate the cost of a lease extension? Yes. The premium is negotiated, usually between valuers, and most claims settle without a tribunal hearing. The strength of your position depends largely on the quality of the valuation evidence supporting your figure.

Should I use a lease extension company? It depends on how much you want to manage yourself. A specialist company can coordinate the process, but it does not replace a RICS valuer or a solicitor. Ask who is doing the valuation and the legal work, and what their qualifications are.

Can I extend my lease before selling my property? Yes, and it is often sensible where the term is short, since it removes a buyer objection. Alternatively, the benefit of a started statutory claim can sometimes be assigned to your buyer. Take advice on which suits your timing.

Conclusion

The lease extension process is more manageable than it first appears, but it rewards preparation. Check your lease, work out the unexpired term precisely, and get a realistic view of the premium before you engage with the freeholder.

Two pieces of professional input usually matter: a valuer to establish what the extension should cost, and a solicitor to handle the procedure and the terms of the new lease. They do different jobs, and both are worth having.

It is also worth being careful about the legal position. Leasehold reform has been widely reported, but much of the Leasehold and Freehold Reform Act 2024 is not yet in force, and claims made now are valued under the existing rules.

If your lease is approaching 80 years, or you are thinking about selling, an early conversation with a RICS-qualified valuer with London leasehold experience will tell you where you stand and what your options are.

This article is general information and not legal or valuation advice. Your circumstances should be discussed with a qualified solicitor and a RICS Registered Valuer with enfranchisement experience.