Asking the seller to start a lease extension before you buy

When you're buying a leasehold flat, the number of years left on the lease isn't just a detail buried in the legal pack. It can make or break your purchase.

Lenders are the main reason. Most mortgage lenders want to see roughly seventy to eighty five years remaining on the lease when you apply, and they also want enough years left at the end of the mortgage term, typically thirty to forty years. Every lender sets their own exact figure, so you need to ask your specific lender what they'll accept. Fall short and they can simply refuse to lend.

Then there's the cost of extending. Once a lease drops below eighty years, something called marriage value kicks in. This is a legal concept that means the leaseholder has to pay the freeholder a share of the uplift in the property's value that the longer lease creates. In plain English, the premium you pay to extend gets significantly more expensive the moment that lease ticks under eighty years. The Leasehold and Freehold Reform Act 2024 was supposed to abolish marriage value, but that provision is not yet in force and has no confirmed start date as of September 2026. So right now, marriage value still applies. Confirm the current position with your solicitor before you rely on anything changing.

All of this means that if you're looking at a flat with, say, seventy two years left, you have a problem. You might struggle to get a mortgage, and extending after you buy will cost more than it would have done a few years ago. But there is a practical workaround, and it involves the seller.

Under the Leasehold Reform, Housing and Urban Development Act 1993, a qualifying leaseholder has the right to extend their lease by ninety years on top of what's left, at a peppercorn ground rent, by serving a formal notice on the freeholder. This is called a statutory lease extension.

The good news is that once that notice has been served, the right it creates belongs to the lease, not just to the person who served it. That means it can be transferred. If a seller serves the initial notice, called a section 42 notice, before contracts are exchanged, they can assign that benefit to you, the buyer, as part of the sale. You then step into their shoes and continue the process through to completion of the lease extension.

This is enormously useful. The seller has already owned the flat long enough to have the right to serve the notice. Since 31 January 2025, the old rule requiring two years of ownership before you could claim a statutory extension was abolished, so you as a buyer could eventually claim one yourself. But in practice, you'd still need to complete your purchase first, then serve your own notice, then wait out the whole process. That takes time, during which your mortgage application might be in limbo. Having the seller start the process before you exchange means the clock is already ticking.

The mechanics aren't complicated, but they do require both sides to be organised and to have good solicitors.

The seller serves the section 42 notice on the freeholder before exchange of contracts. The notice sets out the proposed premium and terms. The freeholder then has two months to respond with a counter notice. None of that needs to have happened before you exchange, but the notice must be served.

At the point of exchange, the contract includes a clause requiring the seller to assign the benefit of the notice to you on completion. Your solicitor will want to see the notice itself, check it was served correctly, and make sure the assignment is properly documented in the transfer.

After completion, you take over the lease extension negotiation. You'll be dealing with the freeholder directly, through your own solicitor, to agree the premium. If you can't agree, either side can apply to the First-tier Tribunal to decide the price. The whole process from notice to completion of the extension can take anywhere from several months to well over a year, depending on how cooperative the freeholder is.

You'll need a specialist leasehold solicitor for the extension itself, which is separate from your conveyancing. Budget for that as an additional cost on top of your purchase legal fees.

This is where having a solicitor who actually knows leasehold law earns their fee. There are several things they must look at carefully.

1. Was the notice validly served? A section 42 notice has strict requirements. It must name the correct landlord, include the right information, and be served in the right way. A defective notice can be invalid, which would mean the whole benefit you thought you were buying doesn't exist.

2. Is the seller actually a qualifying tenant? The seller needs to have held the lease under a long lease, generally one originally granted for more than twenty one years. Your solicitor confirms this from the title documents.

3. Has the freeholder served a counter notice, and if so, what does it say? If the freeholder has already responded, your solicitor needs to review the counter notice and advise on whether the proposed premium looks reasonable or whether you're heading for a tribunal.

4. What is the current lease length, and has marriage value been triggered? Your solicitor should flag whether the lease is under eighty years and what that means for the likely premium you'll pay to extend.

5. Is the assignment clause in the contract watertight? The contract must specifically provide for the assignment of the benefit of the notice. A vague reference isn't enough. Your solicitor should check the wording is clear and enforceable.

6. Are there any ground rent issues on the existing lease? Leases granted before 30 June 2022 may still carry a ground rent. The new extended lease, once completed, will carry a peppercorn ground rent under the statutory process, but you need to know what you're dealing with in the meantime.

Let's be honest about the money, because this process isn't free.

The seller pays to instruct a solicitor to serve the section 42 notice. They'll also typically pay for a specialist leasehold valuer to advise on the premium to propose in the notice. These aren't huge costs but they're real ones, and some sellers will push back on incurring them unless they're confident the sale is going ahead.

You as the buyer will pay the legal costs of the assignment at completion, as part of your conveyancing. After completion, you pay your own solicitor's fees to continue the lease extension negotiation, the freeholder's reasonable legal and valuation costs (yes, you pay those too, that's how statutory extensions work), and ultimately the premium itself.

The premium depends on the lease length, the ground rent, the value of the flat, and whether marriage value applies. There's no standard figure. A specialist leasehold valuer can give you an estimate before you commit to the purchase, and it's genuinely worth paying for that advice. Going in blind on the likely cost of the extension is a risk you don't need to take.

Some buyers try to negotiate a reduction in the purchase price to reflect the cost of the extension. That's a reasonable conversation to have, but it depends on how motivated the seller is and what the market looks like.

Not every short lease situation calls for this solution. It's most useful in a fairly specific set of circumstances.

It works best when the lease has between sixty and seventy nine years left. At that point, you're in marriage value territory, the lender may be nervous, but the flat is still mortgageable with the right lender once an extension is underway. Some lenders will lend on a property where a valid section 42 notice has already been served, even if the extension isn't complete, because the right is now protected and the clock is running. You need to confirm this with your specific lender.

It's less useful if the lease is very short, say under sixty years, because you may struggle to get any lender to consider it at all, even with a notice served. And it's unnecessary if the lease has eighty five or more years left, because you can extend after you buy without the urgency.

The seller also needs to be willing. You can't force them to serve a notice. It's a negotiation, and you may need to make it worth their while, whether through the price or by covering their costs of serving the notice. Frame it as solving a problem for both of you, because it genuinely is.

If you've spotted a flat you love and the lease looks short, here's what to do.

First, check the lease length. You can do a basic search on the HM Land Registry website for free to confirm whether the property is leasehold and get the title number. To see the actual title register with the lease details, you'll pay seven pounds to download it from gov.uk. That seven pounds is well spent before you get emotionally attached.

Second, talk to a specialist leasehold valuer. Get a rough sense of what the extension premium might cost. This doesn't need to be a formal report at this stage, just a ballpark conversation.

Third, raise it with the seller early. Don't wait until you're deep into the legal process. Ask through the estate agent whether the seller would be willing to serve a section 42 notice as a condition of the sale. The earlier this conversation happens, the better.

Fourth, instruct a solicitor who knows leasehold law. Not every high street conveyancer deals with this regularly. Ask specifically whether they handle lease extension assignments and whether they can advise on the validity of a section 42 notice.

Finally, talk to your mortgage broker. Get clarity on what your lender will and won't accept before you fall in love with a flat that turns out to be unmortgageable in its current state.