How to Extend Your Lease in the UK: A Step-by-Step Guide

A lease is a depreciating asset. Every year that passes, the remaining term gets shorter — and with it, the property's value, its mortgageability, and the cost of extending. For millions of leasehold flat owners in England and Wales, understanding how to extend the lease is one of the most financially significant decisions they will make.

The good news: if you have owned your flat for two years, you almost certainly have a statutory right to extend — and that extension adds 90 years to the remaining term for a one-off premium. The process is more navigable than many leaseholders assume, though it does require professional guidance and some patience.

Why Lease Length Matters

When a flat is sold on a leasehold basis, the buyer is not purchasing the bricks and mortar outright — they are buying the right to occupy the property for the duration of the remaining lease. Once the lease expires, the property reverts to the freeholder.

This creates a progressive problem. As the lease shortens:

• Mainstream mortgage lenders become unwilling to lend (most require at least 70–85 years remaining at the end of the mortgage term)
• Buyers without cash financing become locked out, shrinking the buyer pool
• The premium required to extend the lease rises — sometimes significantly
• Property value declines relative to comparable flats with longer leases

A flat that was freely mortgageable at 100 years' remaining lease becomes difficult to sell with 75 years remaining, and potentially unsaleable through conventional channels below 60 years.

The 80-Year Threshold: Marriage Value

The most important number in lease extension is 80 years. When a lease drops below 80 years remaining, marriage value comes into play.

Marriage value is the additional value created by extending the lease — specifically, the increase in the property's value that results from the extension. Below 80 years, the freeholder is entitled by law to 50% of this marriage value as part of the extension premium.

In practical terms, this can add thousands — sometimes tens of thousands — to the cost of extension. A lease that might cost £15,000 to extend at 82 years could cost £25,000 or more at 74 years, depending on the property value and the freeholder's valuation.

Two Routes to Extension: Informal and Formal

There are two ways to extend a lease in England and Wales: the informal route (negotiating directly with the freeholder) and the formal statutory route (using your legal rights under the Leasehold Reform, Housing and Urban Development Act 1993).

The Informal Route

You approach the freeholder (or their managing agent) directly and negotiate a lease extension without invoking your statutory rights. The process is quicker and simpler than the formal route if the freeholder is cooperative, and it gives both parties more flexibility — including the ability to agree on terms that differ from the statutory formula (for example, adjusting the ground rent, if the freeholder agrees to a peppercorn).

Advantages of the informal route:

• Faster — can complete in months rather than the full statutory timetable
• More flexible on terms
• Lower legal costs in straightforward cases

Disadvantages:

• No price cap — the freeholder can ask for whatever they want and you have no formal protection on cost
• The freeholder can withdraw from negotiations at any point
• Some freeholders will use the informal route to extract a premium above what the statutory route would produce
• If negotiations stall, you must start the formal process from scratch

The informal route works well when you have a cooperative freeholder, your lease is not dangerously short (well above 80 years), and you have a solicitor advising you on whether the proposed terms are fair.

The Formal (Statutory) Route: Section 42 Notice

The formal route uses your statutory right under the 1993 Act. It is more procedurally demanding but offers significant protections:

• The freeholder cannot simply refuse to grant an extension
• The premium is determined by a legally prescribed formula (or, if there is a dispute, by the First-tier Tribunal (Property Chamber))
• Once you have served the Section 42 notice, the process cannot be abandoned unilaterally by the freeholder

Eligibility requirements:

• You must have owned the flat for at least 2 years (the date of registration at Land Registry, not the date of exchange or completion)
• The flat must be a residential leasehold property (houses have different, less favourable rights under the same Act — though Leasehold Reform Act changes are altering this landscape)
• The original lease must have been granted for a term of more than 21 years

The Section 42 Process Step by Step

Step 1: Instruct a Leasehold Specialist Solicitor

Before serving the notice, you need a solicitor experienced in leasehold enfranchisement. This is not the same as a general conveyancing solicitor — the 1993 Act process has specific procedural requirements, and errors in the notice can invalidate it entirely.

Your solicitor will carry out preliminary checks: confirming your eligibility, identifying the correct freeholder, and advising on the likely premium range.

Step 2: Commission a Specialist Valuation

Before you serve the Section 42 notice, it is worth getting a valuation from a surveyor experienced in leasehold valuation. This valuation estimates the premium you should expect to pay — it is the basis for your opening offer in the statutory negotiation.

A specialist surveyor (ideally a member of the Royal Institution of Chartered Surveyors with experience in leasehold valuations) will use the statutory formula, which takes into account:

• The ground rent passing
• The unexpired term of the lease
• The open market value of the flat with its current lease
• An estimate of the value of the flat with a 90-year extension at peppercorn ground rent
• Marriage value (if the lease is below 80 years)

Step 3: Serve the Section 42 Notice

Your solicitor serves the formal Section 42 notice on the freeholder (and any intermediate landlord). This notice must contain:

• The tenant's details
• The property details
• The proposed premium (your opening offer)
• Your proposed terms for the new lease

The Section 42 notice triggers a strict legal timetable. The freeholder has 2 months to respond with a counter-notice (Section 45 notice). If they fail to respond within this period, you can apply to court for the terms of the new lease to be determined.

Step 4: Counter-Notice and Negotiation

The freeholder's counter-notice will typically propose a higher premium and may include different terms. This begins a negotiation period — usually conducted between the solicitors and surveyors on each side.

Most lease extensions are agreed by negotiation rather than going to tribunal. The surveyors on each side will typically reach a compromise that reflects the statutory formula, though there is genuine variation in how freeholders approach the negotiation.

Step 5: Application to Tribunal (If Needed)

If the parties cannot agree within a 6-month window from the date of the counter-notice, either party can apply to the First-tier Tribunal (Property Chamber) to determine the premium. Tribunal is time-consuming and adds to costs, but it protects leaseholders from having to accept an inflated premium.

Step 6: Completion of the New Lease

Once the premium and terms are agreed (whether by negotiation or tribunal determination), the new lease is drafted and completed. The new lease adds 90 years to the unexpired term and reduces the ground rent to a peppercorn (effectively zero).

Costs of Lease Extension

The total cost of a lease extension involves several components.

The Premium

This is the payment to the freeholder for granting the extension. It is the most variable element, depending on:

• Property value
• Current lease length
• Ground rent
• Whether marriage value applies

Rough premium ranges as a guide (not a substitute for a proper valuation):

These figures are illustrative only — the premium depends heavily on the specific property, ground rent, and freeholder.

Legal Costs

You pay your own solicitor's fees, and by statute you also pay the freeholder's reasonable legal costs. Combined solicitor costs typically run to £3,000–£6,000 for a straightforward case.

Valuation Costs

Your surveyor's fee for the valuation and negotiation work: typically £1,500–£3,500.

Registration

The new lease must be registered at Land Registry: approximately £100–£500 depending on the premium.

Total typical range: For a straightforward extension on a lease of 75–85 years on a £300,000 flat, total costs are often in the range of £10,000–£25,000. For shorter leases or higher-value properties, costs can be significantly higher.

The Leasehold Reform Act Changes

The Leasehold and Freehold Reform Act 2024 made significant changes to the leasehold system in England and Wales:

• Marriage value has been abolished for statutory lease extensions — meaning the 80-year threshold is significantly less financially significant for extensions completed under the new rules. The implementation timeline for this specific provision should be confirmed with a solicitor, as the Act's various provisions are being brought into force in stages.
• Higher maximum extension terms may become available, potentially replacing the 90-year statutory extension with a longer period
• Changes to ground rent rules affect what freeholders can charge in new leases

The leasehold reform landscape is evolving rapidly. If you are considering a lease extension, taking advice from a specialist solicitor who is up to date with the current implementation position is particularly important.

Where to Get Help

LEASE (the Leasehold Advisory Service) is a publicly funded body that provides free, independent advice to leaseholders in England and Wales. Their website has guidance on the statutory process, and they offer a free advice line for leaseholders with questions. This is typically the most useful first port of call.

Homehold and Legal Brokers are examples of specialist leasehold services that can help leaseholders navigate the process and connect with appropriate solicitors and surveyors.

The Bottom Line

A lease extension is one of the most financially significant decisions a flat owner can make — both in terms of the cost of the extension itself and the impact on the property's value and mortgageability. Extending before the lease drops below 80 years is generally strongly worth considering, and the statutory route provides meaningful protections that the informal route does not.

The process is navigable with the right professionals. The key is to start early — before a sale or remortgage creates urgency — and to use a solicitor and surveyor who genuinely specialise in leasehold.

This is educational content, not legal advice. Lease extension involves complex statutory law — speak to a qualified leasehold solicitor and, where relevant, a specialist surveyor before making any decisions.