Broadband Provider, the broadband news and comparison website, has released a map showing the relationship between connection speeds and property values. And for London’s flat-heavy boroughs, where gigabit availability still lags the national average despite the capital’s sky-high prices, the findings carry a significant financial implication for sellers.
How broadband speeds affect London property prices
Sources: Imperial College London / LSE (property price premium research, 1m+ transactions); Housesimple (ultra-slow speed discount); Openreach / Ofcom (MDU access data). London premium reflects buyer willingness-to-pay in the capital vs national average.
The relationship between broadband speed and property value is better evidenced than most sellers and their agents realise. Research from Imperial College London and the LSE, drawing on over a million English property transactions across a fifteen-year period, found that UK property prices increase on average by around 3% when internet speed doubles, with London buyers demonstrating a willingness to pay a premium of up to 8% for properties in areas offering fast internet.
At London prices, that premium is not a rounding error. An 8% discount on an average London property worth £520,000 represents over £40,000. The figure is considerably larger on the kind of higher-value stock that dominates the inner boroughs.
The downside equivalent is starker still. Research by online estate agent Housesimple found that houses with ultra-slow speeds of under 1Mbps were valued on average 24% less than properties in areas with fast connections. Streets with genuinely inadequate broadband are, in effect, carrying a structural discount that no amount of renovation will address.
London’s flat problem
Broadband Provider, which tracks UK rollout data and coverage developments, has highlighted a structural issue that disproportionately affects London: the access problem in multi-dwelling units. Openreach has reported that there are over 800,000 flats in the UK where its fibre network is present in the street outside the building, but it cannot gain access to connect the properties inside. The fibre passes the front door. It does not come through it.
How to read this: Boroughs further right have a higher proportion of flats, making them more likely to have Openreach fibre passing the street but unable to enter the building. Boroughs higher up carry greater financial exposure when connectivity lags.
The scale of that problem is concentrated in exactly the areas where London’s housing stock is densest. Data from Ofcom shows that postcodes where over three quarters of premises are flats had lower gigabit broadband availability than areas with fewer flats, and that understates the gap because flats are more likely to be in urban areas which have higher gigabit availability on average. London is the most flat-heavy major city in the country. The boroughs where mansion blocks, purpose-built flats and converted Victorian terraces dominate the stock are precisely the ones where the access problem is most acute and least visible to buyers during a standard viewing.
The issue is legal as much as practical. The Telecommunications Infrastructure (Leasehold Property) Act 2021 introduced a process allowing broadband companies to gain access to residential buildings via the courts, where a resident has requested broadband but the owner does not respond. It does not apply if the freeholder has refused permission or cannot be identified. In practice, a leaseholder who wants full fibre but has a non-cooperative freeholder is stuck, and so is their eventual buyer.
The coverage gap London doesn’t expect
The assumption that London, as the UK’s most connected city, is ahead of the curve on full fibre is not universally supported by the data. Point Topic’s Q2 2025 analysis found that Openreach FTTP coverage is highest in local authorities outside London and the South East. Meanwhile, Ofcom’s Connected Nations 2025 report noted that full fibre availability varies significantly across England’s 296 local authorities, with Kingston upon Hull at 99% and Harlow at the bottom of the table.
London sits in neither extreme, but it is not uniformly connected. Pockets of the capital, particularly in older, leasehold-heavy areas with unresponsive freeholders and complex building infrastructure, remain on copper or on part-fibre FTTC connections that deliver speeds well below what buyers in 2026 expect as standard.
What this means for asking prices
The practical implication for sellers is that broadband availability is now a checkable, comparable specification in the same way EPC rating is. Buyers can look up any address on the Ofcom checker before viewing. Where a property shows limited speed options, the comparison with a fibre-connected alternative around the corner is immediate and quantifiable.
Broadband Provider’s coverage of the rollout and its property implications is worth following for anyone buying or selling in a London postcode where the connection speed is ambiguous. The question most sellers are not asking is whether their asking price already reflects a discount that could be closed with a single freeholder conversation.