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Independent data from Thinkbroadband has today revealed 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 March 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.
NOTE: At the end of 2024 around 74% of the UK could access a full fibre network, rising to 86% for gigabit-capable broadband (here) – the latter combines FTTP/B and Hybrid Fibre Coax (cable).
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.
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The latest State of Broadband Report (March 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.
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Finally, we’ve included TBB’s previous figures from July 2024, which help to show whether or not a network operator has slowed its pace of build or even stalled.
Top 17 Largest UK Full Fibre Networks by Coverage – March 2025
Operator Premises Mar 2025 (Jul 2024) – TBB Analysis Official Claim
Openreach (BT) 17.1 million (14.8m) 17m – Jan 2025
CityFibre 4m (3.4m) 4.4m (4.2m RFS) – Mar 2025
Netomnia (YouFibre) + Brsk 2.03m (1.68m) 2.2m RFS – Mar 2025
Virgin Media (RFOG) 1.7m (1.6m) It’s complicated (see below)
Nexfibre (Virgin Media) 1.6m (1.1m) 2m – Jan 2025
CommunityFibre 1.5m (1.5m) 1.3m – Oct 2024
Hyperoptic 1.2 (1.1m) 1.73m – Jul 2024
FullFibre Limited + Zzoomm 598,000 (581,000) 600,000 RFS – Jan 2025
Gigaclear 557,000 (508,000) 593,000 RFS – Mar 2025
Trooli 441,000 (421,000) 410,000 – Mar 2025
Fibrus 399,000 (353,000) 400,000 – Dec 2024
AllPoints Fibre 298,000 (289,000) none given
KCOM 283,000 (281,000) 305,000 – Nov 2024
F&W Networks 269,000 (238,000) 410,000 RFS – Feb 2024
G.Network 252,000 (250,000) 361,000 – Mar 2024
Toob 229,000 150,000 – Aug 2023
Grain (Grain Connect) 222,000 (211,000) 220,000 RFS – May 2024
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 (it’s only now starting to go live), and thus TBB has only included the figure for their older Radio Frequency Over Glass (RFOG) based FTTP build and not the HFC upgrades.
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Meanwhile, the nexfibre build is technically a separate company and so gets its own entry, despite only selling packages via Virgin Media (more ISPs will join this year). Officially, Virgin Media and Nexfibre claim to have passed a total of 6.4 million premises with FTTP (as above, the missing gap above reflects Virgin Media’s HFC to XGS upgrades), which is up from 5 million in July 2024.
Elsewhere, we’re now treating Netomnia and Brsk as a single operator post-merger, while we’ve also done the same for FullFibre and Zzoomm due to their recent consolidation. The table also now includes toob, which is useful because the last time we had an official build update from them was in August 2023.
Broadly speaking, most of the listed operators seem to be tracking close enough to their official claims to be reflecting reality, although G.Network, F&W Networks and Hyperoptic’s official vs estimated coverage data continues to show wide gaps.