How long a lease extension takes, a buyer's complete guide

If you're buying a leasehold flat, the length of the lease isn't just a number on a piece of paper. It affects whether you can get a mortgage, what you'll pay to extend later, and how easy the flat will be to sell when the time comes. So understanding how long an extension actually takes isn't just interesting background knowledge. It's genuinely useful, because it shapes what you should be asking the seller to do before you even exchange contracts.

The short version is this: the statutory route typically takes six months to a year, sometimes longer if things get complicated. The informal route can be quicker, sometimes just a few months, but it comes with less legal protection. Neither is instant, and that's exactly why buyers often need to get the ball rolling well before they own the flat.

The statutory route is the formal, legally protected process set out in the Leasehold Reform, Housing and Urban Development Act 1993. It gives qualifying leaseholders the right to extend by ninety years on top of what's left, at a peppercorn ground rent, and the freeholder can't simply say no.

Here's roughly how the timeline unfolds once a leaseholder serves the formal notice, called the Section 42 notice.

1. 1Section 42 notice served. The leaseholder's solicitor serves this on the freeholder. It sets out the proposed premium and starts the statutory clock.
2. 2Freeholder has two months to respond. They must serve a counter-notice by a deadline specified in the Section 42 notice, which must be at least two months away. The counter-notice accepts the claim or disputes it.
3. 3Negotiation period. Both sides negotiate the premium, usually with specialist surveyors. This is often where time slips away. There's no fixed deadline for agreeing a figure, and if the freeholder is slow to engage or appoints a surveyor late, weeks can drift by.
4. 4Six-month window to apply to the tribunal. If the parties can't agree, either side can apply to the First-tier Tribunal (Property Chamber) to determine the premium. This window opens two months after the counter-notice and closes six months later. Tribunal proceedings add months to the process.
5. 5Completion. Once the premium is agreed or determined, both sides have two months to complete the new lease.

All in, a relatively smooth statutory extension, where the freeholder engages promptly and both surveyors reach agreement without tribunal involvement, can take around six to nine months. Add a tribunal application and you're realistically looking at twelve to eighteen months or more. That's a long time to be in limbo.

The informal route means simply approaching the freeholder and negotiating a lease extension without serving any formal statutory notice. No prescribed forms, no statutory timetable, no automatic right to go to the tribunal if talks break down.

When it works, it's genuinely quicker. A co-operative freeholder and a motivated seller can sometimes get a deal done in two to four months. The premium might be similar to what you'd pay on the statutory route, or it might not. Because there's no tribunal backstop, the freeholder knows you have less leverage, and some will price accordingly.

The other thing to watch is the terms. On the statutory route, the ninety-year extension and peppercorn ground rent are set in law. Informally, the freeholder can offer, say, a shorter extension or try to retain a ground rent on the new lease. For leases granted from 30 June 2022, the Leasehold Reform (Ground Rent) Act 2022 requires a peppercorn ground rent, but for existing leases being extended informally, the freeholder may attempt to include a ground rent clause. Your solicitor needs to check this carefully.

The informal route suits situations where the freeholder is known to be reasonable, the lease isn't critically short, and speed matters more than squeezing every penny. It's not right for everyone.

Here's the clever bit that many first-time buyers don't know about. Since 31 January 2025, the rule that you had to own a flat for two years before claiming a statutory lease extension was abolished. That means a seller can serve the Section 42 notice and then assign the benefit of that claim to you as the buyer. You pick up the process mid-stream rather than starting from scratch after completion.

Why does that matter? Because if the lease has fewer than eighty years left, every month that ticks by increases the premium you'll pay. Once a lease drops below eighty years, marriage value kicks in, which can add a substantial sum to the extension cost. The Leasehold and Freehold Reform Act 2024 does abolish marriage value, but that provision is not yet in force and has no confirmed start date as of September 2026, so you absolutely cannot rely on it. Confirm the current position with your solicitor before making any assumptions.

Asking the seller to serve the Section 42 notice before exchange also locks in the valuation date. The premium is calculated based on the lease length and property value at the date the notice is served, not at the date you complete your purchase. If values are rising, serving early can save you money.

In practice, you'd typically negotiate with the seller for them to serve the notice as a condition of the sale, or at least as a goodwill gesture. Your solicitor and theirs then need to agree how the claim is assigned to you at completion. It adds a layer of conveyancing complexity, but it's well worth it when the numbers are tight.

Even when everyone wants to get things done, lease extensions have a habit of dragging. Here are the most common culprits.

Freeholder delays. Some freeholders, particularly large investment companies or absentee landlords, are slow to appoint solicitors and surveyors. There's no statutory penalty for dragging their feet during the negotiation phase.

Difficulty tracing the freeholder. If the freehold has changed hands or the freeholder is overseas, just getting the notice served correctly can take weeks.

Surveyor disagreements. Lease extension valuations involve genuine professional judgment, and two surveyors can reach quite different figures. If neither side budges, the tribunal is the only answer, and that takes time.

Missing documents. Your solicitor will need to check the title register and the existing lease. If filed documents are missing or the title has historic defects, that creates extra work. Downloading the title register, title plan or a copy of a filed lease from HM Land Registry costs seven pounds per document on gov.uk, so it's cheap to check early.

Mortgage lender requirements. Most lenders want around seventy to eighty-five years left on the lease when you apply, and enough years remaining when the mortgage ends, typically thirty to forty years, though each lender sets its own figure. If the lease is borderline, your lender may insist the extension completes before they'll release funds, which ties the whole purchase to the extension timetable.

If you're buying a leasehold flat and the lease length is a concern, here's what to do.

1. 1Find out the exact lease length. Ask the estate agent and check it against the title register. A basic search on the Land Registry's free property search tool shows whether it's freehold or leasehold and gives you the title number, then you can pay seven pounds to download the full register.
2. 2Ask the seller whether they've already started an extension. If not, ask whether they'd be willing to serve the Section 42 notice before exchange.
3. 3Instruct a solicitor with leasehold experience early. Not all conveyancers handle lease extension assignments regularly. You want someone who does.
4. 4Get a specialist surveyor to estimate the premium. This is separate from your mortgage valuation and worth every penny. You need to know what the extension will cost before you commit.
5. 5Talk to your mortgage broker about the lender's requirements. If the lease is short, some lenders won't touch it at all. Better to know now than after you've paid for a survey.
6. 6Build the extension timeline into your purchase plan. Don't assume it'll be sorted in a month. It probably won't be.

There's no magic shortcut that makes a lease extension quick and cheap and risk-free all at once. The statutory route is slower but gives you proper protection. The informal route is faster but requires a co-operative freeholder and careful attention to the terms you're agreeing to.

What you can control is how early you start. Asking the seller to serve the Section 42 notice before exchange is one of the smartest moves a buyer can make when the lease is getting short. It locks in the valuation date, keeps the statutory clock ticking, and means you're not starting from zero the moment you pick up the keys.

Leasehold law is also genuinely in a period of change right now. The Leasehold and Freehold Reform Act 2024 introduced significant reforms, but not all of them are in force yet, and the position can shift. Always confirm the current rules with a solicitor who specialises in this area before making any decisions based on what you've read, including here.