Top 17 Largest UK Full Fibre Broadband Networks by Coverage – H2 2025

The latest independent data from Thinkbroadband has today helped us to produce an updated assessment of how big – in terms of network coverage (premises passed) – the top 17 largest Fibre-to-the-Premises (FTTP) based broadband ISP networks in the UK have become by September 2025. Once again, we compare this data against official coverage claims.

One of the difficulties with keeping close tabs on the rapid growth of UK full fibre networks is that some operators often make coverage claims that are difficult to independently verify. Similarly, we’ve often found that the official “premises passed” figures put out by some of those providers may not always reflect reality.

For example, in some cases official figures can include partially built areas that aren’t fully live yet and, in other cases, the network may be technically built, but customers in some of the covered areas won’t be able to get it ordered or installed by an ISP (i.e. not yet truly “Ready for Service” – RFS). Similarly, in a smaller number of cases, operators can sometimes make mistakes in their data.

The latest State of Broadband Report (September 2025) from TBB is thus quite useful because we get an up-to-date summary of how much coverage has been independently verified to exist (RFS) across the largest alternative network (altnet) operators in the full fibre space. We can then compare TBB’s data with the official coverage claims from operators.

Naturally, there are some caveats to consider when doing this, which need to be reflected. Firstly, TBB is not perfect, and they do sometimes miss bits and pieces of network coverage (please email them if you spot this). Secondly, conducting independent analysis of network builds like this is slow and laborious work, thus over the years we’ve tended to perceive that TBB’s latest data can be up to 2-3 months behind actual build.

Such a time lag, which will vary between operators, may not seem like much, but it can create large gaps between independent and official figures. Such gaps are most likely to occur during the early ramp-up phase of a new network build, where smaller networks may – over the course of a year – go from having a few tens of thousands of premises passed to hundreds of thousands (very few operators are in that phase today).

Suffice to say, it’s wise not to make the mistake of automatically inferring that a big gap is because an altnet may be overstating their coverage. In addition, we’ve also dated the official claims below as most operators only very occasionally provide an official update on their build progress and some haven’t done one in a long time, which will thus be out of step with TBB’s latest modelling.

Finally, we’ve included TBB’s previous figures from March 2025, which helps to show whether a network operator has slowed its pace of build or even stalled.

Top 17 Largest UK Full Fibre Networks by Coverage – H2 2025

As usual, we aren’t going to micro analyse each operator above and, in any case, most of TBB’s real-world focused estimates of Ready for Service (RFS) coverage are roughly where we’d expect them to be when compared with official claims. But there are a few caveats to point out for certain operators.

Firstly, Virgin Media’s network is currently in the middle of a major upgrade, which is seeing XGS-PON based FTTP being deployed into areas that could previously only access their Hybrid Fibre Coax (HFC) network. Currently, it’s a little bit difficult to accurately track these XGS areas, and thus TBB has only included the figure for their older Radio Frequency Over Glass (RFOG) based FTTP build.

Meanwhile, the nexfibre build is technically a separate company and so gets its own entry, despite only selling packages via Virgin Media and giffgaff. Officially, Virgin Media and nexfibre claim to have passed a total of over 7 million premises with FTTP (as above, the missing gap above reflects Virgin Media’s HFC to XGS upgrades).

Otherwise, G.Network, F&W Networks and Hyperoptic’s official coverage data continues to show some extremely wide gaps from TBB’s real-world analysis. Suffice to say, it’s often wise to take any coverage claims from these operators with a pinch of salt.

Finally, Freedom Fibre is still missing off the table, despite officially claiming to have covered 350,000 premises (Jun 2025); this may be partly due to issues with the network integration of VXFIBER’s base. But TBB currently measures them as 236,000 premises and told us that they’ll probably make the next report in 2026. Other altnets currently remain too small to be included.