England’s Flat Slump Is Becoming a Mortgageability Problem, Not Just a Sales Problem

A flat can be affordable, well located and occupied by a financially strong borrower yet still produce a mortgage decline. As England’s leasehold flat market becomes increasingly illiquid, lease length, service charges, building safety, ground rent, commercial premises and resaleability are becoming central mortgage questions at both purchase and refinance.

New reporting on England’s flat market has exposed an unusually severe divide between flats and houses, with owners in some areas struggling to sell despite repeated price reductions.

The Guardian reported this weekend that Zoopla analysis found an average of 80.5% of leasehold flats listed during 2025 across the areas studied had not sold within six months. London was the weakest market, where approximately 87% remained unsold after six months, followed by the South East at 85% and the East of England at 84%.

At first glance this looks like a property-market story about weak demand and sellers refusing to accept lower prices. But for mortgage borrowers, landlords and owners approaching refinance, a more important issue sits underneath the transaction data.

Some flats are becoming harder for lenders to accept as mortgage security.

The Borrower May Be Mortgageable. The Flat May Not Be.

Residential mortgage underwriting has two fundamental components. The lender assesses whether the borrower can repay the loan, but it also assesses whether the property represents acceptable security.

Those are different questions.

A borrower can have excellent income, a substantial deposit and a strong credit profile but still receive a mortgage decline because of something within the property itself.

With houses, security issues certainly occur, particularly with unusual construction or significant defects. Flats introduce another layer because the lender is not assessing only the internal accommodation. It may also need to understand the lease, freehold, management structure, service charges, building condition, common areas, external wall system, other uses within the building and the future market for the property.

That distinction becomes particularly important when market liquidity weakens. A lender ultimately needs confidence that its security could be sold if the mortgage went into default. If the pool of potential future buyers is already restricted by mortgage criteria, the property's marketability can itself become an underwriting concern.

England’s Flats Are Already Selling More Slowly Than Houses

Zoopla’s own research shows that the divergence between flats and houses is no longer marginal.

Analysis published in June found that houses now cost approximately 1.7 times the price of a typical flat nationally, the widest gap in around 30 years. Flat prices have increased only a little over 10% since 2016, compared with approximately 43% for houses.

In England, flats also take longer to sell. Zoopla reported typical selling periods of around 45 days in London and 49 days in the South East for flats marketed for less than six months, compared with approximately 37 days for houses in both regions.

The problem is therefore not simply that flat prices have failed to keep pace with houses. A weaker resale market can feed directly into lender and valuer perceptions of security.

Lease Length Can Alter Both Value and Lender Appetite

Remaining lease term is one of the clearest examples of a property issue affecting finance.

Government guidance warns that mortgage lenders are less likely to provide finance where a lease has less than 80 years remaining. Zoopla has also reported that roughly a fifth of leasehold listings have less than 100 years left.

The relevant calculation is not always simply the number of years left today. Some lenders also require a specified term to remain at the end of the proposed mortgage.

A borrower considering a 30-year mortgage on an 85-year lease can therefore face a different lender universe from an otherwise identical borrower purchasing a flat with a 150-year or 999-year lease.

For an existing owner, this creates a refinancing question. A flat financed comfortably several years ago may now have crossed into a lease bracket that fewer lenders find acceptable.

Extending the lease can therefore be a finance decision as well as a legal or resale decision.

High Service Charges Can Become a Finance Issue

Service charges are another increasingly important part of flat ownership. Zoopla recently estimated that the typical leaseholder pays around £1,900 a year in service charges, with ground rent adding a further typical cost for many existing leases.

In premium apartment buildings, the sums can be materially higher, particularly where developments include lifts, concierge services, private gardens, gyms, swimming pools or extensive communal areas.

Service charges can affect financing in more than one way.

First, they form part of the owner's recurring housing expenditure. Secondly, unusually high or rapidly rising charges can discourage future buyers. Thirdly, major works or large anticipated expenditure can affect both valuation and marketability.

A £750,000 flat with a modest and stable service charge is therefore not necessarily the same mortgage proposition as a £750,000 flat carrying £12,000 or £15,000 a year of ongoing charges.

The headline property value alone does not tell the whole credit story.

Ground Rent Terms Still Need Careful Review

Ground rent has been heavily reformed for new leases, with most new residential leases granted from 30 June 2022 restricted to a peppercorn ground rent.

Existing leases can be different.

Older leaseholders may still have contractual ground rent, including provisions allowing increases over time. Government guidance explicitly notes that the amount of ground rent and the way it increases can make lenders less willing to provide mortgages on a leasehold property.

The issue is therefore not simply the current annual payment. The review mechanism written into the lease can matter.

For purchasers and existing owners, this reinforces the importance of examining the lease itself rather than relying only on the estate-agent particulars.

Building Safety Has Improved, but It Has Not Disappeared From Underwriting

Building-safety concerns remain another major consideration for some blocks.

The position has improved substantially since the most severe period of post-Grenfell mortgage restrictions. Government protections and industry agreements have reopened lending on many affected buildings.

Government guidance confirms that a number of major lenders have agreed to lend on buildings in England of 11 metres or more where specified remediation or leaseholder-protection conditions are met.

That does not mean every building with a historic safety issue is now automatically acceptable.

The lender still needs the appropriate evidence, and the valuer must be comfortable with the property. Documentation, remediation status, qualifying leaseholder protections and the nature of any remaining works can therefore be critical.

For owners approaching refinance, identifying missing building-safety documents late in the process can delay or narrow the mortgage options available.

Flats Above Commercial Premises Can Have a Smaller Lender Pool

One of the clearest examples in the latest Guardian reporting involved a leasehold property above commercial premises where mortgage availability was restricting the pool of potential purchasers.

This is a familiar specialist-lending issue.

Flats above or adjacent to shops, restaurants, takeaways, pubs, offices, workshops and other commercial uses are not treated identically across the mortgage market.

The nature of the business matters because a lender and valuer can consider noise, smells, opening hours, access, future change of use and the impact on resale demand.

A quiet professional office beneath a flat may produce a very different underwriting response from a late-night bar or hot-food takeaway.

Some lenders consider such properties subject to valuation, while others have tighter restrictions. Current mortgage criteria research describes these cases as frequently being assessed individually, with location, access and commercial use influencing acceptability.

The practical consequence is significant. If only part of the mortgage market will lend, the number of future purchasers capable of completing on the property falls.

That is why mortgageability and resaleability become connected.

A Valuer Can Change the Entire Refinance

Borrowers sometimes assume that obtaining an Agreement in Principle means the mortgage is substantially agreed.

On a flat with unusual property characteristics, the valuation can be the point at which the case changes.

A valuer may conclude that the property is suitable security but assign a lower value than expected. Alternatively, the valuer may raise concerns about marketability, commercial surroundings, construction, building condition or another feature.

A down valuation is particularly important at refinance because it can increase the effective loan-to-value without the borrower increasing their debt.

Consider an owner with a £400,000 mortgage who believes the flat is worth £600,000. That implies an LTV of approximately 67%.

If a new lender values the property at £500,000 because of weaker market evidence or property-specific concerns, the same £400,000 mortgage is suddenly at 80% LTV.

The borrower has not changed. The debt has not changed. The valuation has changed the available mortgage market.

This Can Be More Serious at Refinance Than at Purchase

Purchasers have one major advantage: they can decide not to proceed.

An existing owner cannot simply walk away from the property when the fixed-rate mortgage expires.

This is where flat mortgageability becomes particularly important.

A borrower may have taken a perfectly conventional mortgage five years earlier. Since then, the lease has shortened, service charges may have increased, new building-safety information may have emerged, lender criteria may have changed and flat values may have performed weakly.

The owner can therefore arrive at refinance with excellent personal affordability but discover that fewer lenders accept the security.

The Product-Transfer Trap

Where external refinancing becomes difficult, an existing lender's product transfer can become particularly important.

A product transfer can sometimes allow an existing borrower to move to a new rate without undertaking the same full property assessment required by a new lender, depending on the circumstances and whether additional borrowing or other changes are requested.

That can provide a valuable route for an owner whose property is difficult to refinance elsewhere.

But dependence on the incumbent lender reduces optionality. The borrower may not have access to the most competitive rate available across the wider market, and raising additional capital can be more complicated.

For HNW borrowers and landlords who expected to release equity from an apartment, this distinction can materially affect wider financial plans.

Capital Raising Can Be Hit Before the Existing Mortgage Is

Some owners do not need to move lender simply to obtain a better rate. They need to raise capital.

A landlord may want funds for another acquisition. A homeowner may be financing renovation, tax liabilities or another property transaction. An HNW client may want to restructure debt across a wider balance sheet.

In these circumstances, the lender must be comfortable not only with the existing debt but also with the increased facility.

A conservative valuation or narrower security appetite can therefore restrict capital raising even where a straightforward product transfer remains available.

HNW Apartments Are Not Immune

Mortgageability problems are not limited to low-value flats.

Prime London apartments can involve their own complexities: substantial service charges, sophisticated freehold arrangements, large blocks, overseas ownership concentrations, extensive facilities and values that depend on a comparatively narrow buyer market.

The borrower may have substantial income and assets, but the lender still has to accept the specific apartment as security.

For larger loans, a private bank may be able to consider the client's wider assets and relationship, while specialist lenders may have greater flexibility around particular property characteristics.

But specialist or private-bank appetite should not be confused with automatic acceptance. Valuation and exit-market considerations remain important.

Landlords Face a Strategic Decision, Not Just a Mortgage Decision

The current market is especially relevant to professional landlords holding leasehold apartments.

A flat purchased as an investment 10 or 15 years ago may now have a shorter lease, higher service charges and a weaker resale market. At the same time, the landlord may face refinancing costs and wider changes in the economics of private renting.

The correct question may therefore be broader than which lender offers the lowest buy-to-let rate.

The owner may need to decide whether to refinance, extend the lease, refurbish, retain, restructure the debt or sell.

If a lease extension improves both mortgageability and resaleability, the cost can potentially be assessed against the value of retaining wider lender access.

Equally, substantial refurbishment may improve the internal condition of a flat but do little to overcome a structural lease, building or commercial-premises issue.

Capital expenditure therefore needs to be directed at the factor actually constraining the property.

A Cheap Flat Is Not Necessarily a Financeable Flat

Weak flat values can create attractive buying opportunities. Zoopla describes the current price gap between flats and houses as the widest in decades.

But price alone should not drive the decision.

A buyer can negotiate a substantial discount and still discover that mortgage lenders will not accept the property. In some cases, this can explain why a flat appears unusually cheap relative to surrounding properties.

The purchase should therefore be tested against both current mortgage availability and likely future refinance and resale routes.

A property that can only be financed by a very small number of lenders today may create the same issue again when the owner eventually wants to remortgage or sell.

Mortgageability Should Be Checked Before the Buyer Incurs Significant Costs

For non-standard flats, the finance review should begin before a buyer becomes heavily committed to legal, valuation and survey costs.

The key is to identify the characteristics that can affect security acceptability and then test those against lender criteria.

This is particularly important for flats over commercial premises, short leases, high-rise blocks, buildings with safety histories, unusual construction, very high service charges and properties where the valuer may have limited comparable evidence.

A specialist mortgage assessment cannot guarantee a valuation outcome, but it can reduce the risk of submitting an application to a lender whose criteria are plainly incompatible with the property.

Estate Agents Can Benefit From Testing Financeability Earlier

The current flat-market slowdown also creates an introducer opportunity for estate agents.

An agent can spend months marketing a property, agree a sale and then lose the transaction because the buyer's lender rejects the security.

If the property has characteristics known to restrict lender appetite, identifying that before accepting an offer can help establish whether the purchaser has a realistic financing route.

This is particularly relevant where a property sits above commercial premises or has a short lease, unusual construction, building-safety history or another feature likely to attract valuation scrutiny.

Lease-Extension Solicitors Can Identify Refinance Risk Early

Solicitors advising on lease extensions are also well placed to identify clients whose motivation is ultimately financial rather than purely legal.

A homeowner may want a longer lease because they are preparing to sell. Another may need it because their mortgage is approaching maturity and the existing term is reducing lender choice.

Understanding the mortgage implications alongside the legal process can help the client assess whether to extend before refinancing or whether an appropriate lender exists under the current lease.

Managing Agents and Block Managers Hold Critical Information

Mortgage delays frequently arise because important block information is not available quickly.

Service-charge accounts, planned works, building insurance, fire-safety documentation and management information can all become relevant during conveyancing and lender due diligence.

For a refinancing borrower, obtaining the relevant documentation before the mortgage application reaches an advanced stage can reduce the risk of last-minute delays.

Surveyors Are Increasingly Central to the Outcome

The latest Guardian reporting also highlights concern about flats being down-valued.

That matters because the lender is relying on the valuer not merely to identify a number but to provide an opinion on whether the property represents suitable security.

In a market with weak transaction volumes, establishing a confident value can become harder because there may be fewer recent comparable sales.

This creates a feedback loop. Weak liquidity can lead to more cautious valuations, cautious valuations can reduce mortgage availability, and restricted mortgage availability can further narrow the buyer pool.

The Current Flat Market Is Not Uniform

It is important not to conclude that all flats are becoming unmortgageable.

They are not.

Zoopla itself emphasises that a well-managed building with a long lease and stable service charges is a materially different proposition from a property carrying lease uncertainty or less predictable costs.

Many flats remain straightforward mortgage security and can represent a more affordable route into home ownership.

The important change is that buyers and owners need to distinguish between price weakness and property-specific mortgageability.

Lower Prices Can Also Create Opportunity

The widening discount between houses and flats means the current market is not solely negative.

For buyers prepared to undertake detailed due diligence, a long-lease apartment in a well-managed building with stable charges and strong mortgage availability may offer considerably better value than an equivalent house.

Investors may also identify opportunities where the property is financeable but seller sentiment has weakened because of the wider flat market.

The distinction is crucial. A flat discounted because the entire sector is out of favour can represent an opportunity. A flat discounted because only cash buyers can purchase it requires a fundamentally different risk assessment.

Owners Should Review Mortgageability Before Their Fixed Rate Ends

Existing flat owners should not necessarily wait until a mortgage deal is weeks away from expiry before investigating the next refinance.

Where the property has a lease approaching a critical term, unusual service charges, building-safety issues or commercial premises within the development, earlier review can provide time to resolve problems.

That might mean commencing a lease extension, obtaining missing documentation, understanding anticipated major works or establishing whether specialist lenders are likely to be required.

For HNW borrowers or landlords with larger portfolios, it can also mean deciding whether the flat should continue to form part of the long-term property strategy.

Mortgageability Is Becoming Part of Asset Management

The broader lesson is that mortgageability should not be treated as a one-off issue resolved on the date of purchase.

For leasehold flats, the underlying security changes over time.

The lease shortens. Service charges change. Buildings require capital expenditure. Regulations evolve. Commercial tenants change. Lender criteria move. Local demand can strengthen or weaken.

For investors and HNW owners, monitoring those factors is increasingly part of sensible asset and liability management.

The Practical Lesson for Buyers and Existing Owners

England’s weak flat market should not be interpreted as evidence that flats cannot be financed.

It does show why the property itself needs to be underwritten before a buyer or owner assumes that strong personal finances will deliver a mortgage.

Two borrowers can have identical incomes and deposits yet receive different outcomes because they are buying different flats.

Equally, two flats carrying the same £500,000 valuation can produce completely different lender responses because one has a long lease, modest charges and straightforward residential surroundings while the other has a shorter lease, high service charges and commercial premises beneath it.

The borrower is only half of the mortgage equation.

In a market where more flats are taking longer to sell, understanding the security is becoming just as important as understanding the person borrowing against it.