BT’s accountants to the rescue: UK broadband trends Q1 2025

The ‘big 4’ ISPs’ combined revenue remained in decline in Q4 2024 at -0.4%, partly due to a BT accounting quirk but mainly due to altnets gaining share

ARPU growth of 2% is roughly compensating for subscriber declines of 2%, but this ARPU growth is likely to weaken in 2025 as various boosts drop out

A recovery will come as the altnets slow in H2 2025 (if not before) due to their restrained expansion, which cannot come soon enough for the big ISPs

The mid-sized UK altnets Zzoomm and FullFibre have agreed to merge, in what looks like an all-share merger of (nearly) equals, both of whom have been struggling to raise finance.

Why did they pick each other rather than the larger CityFibre/Netomnia/nexfibre options? Valuation may have been the key factor, but it has left them still vulnerably low scale with further consolidation necessary.

Much more consolidation is required for the sector to be sustainable in our view, and further financial distress may be required for realistic valuations to emerge.

The largest UK altnets are now all at or close to EBITDA positive, but still heavily cashflow negative even pre-interest costs and with paused builds, due to various below-the-line cash costs requiring continuous funding. EBITDA margins of as much as 35%+ are required to actually be cashflow breakeven.

Altnet economics are still challenging even if debts are fully written off, with a payback of more than 5 years on customer acquisition and connection costs alone.

The consolidation endgame is increasingly imminent, with the outcome likely to be a mix of CityFibre/VMO2 acquisitions, stand-alone niche players continuing, and abandoned assets, with the outcome for the rest of the sector more benign under any scenario than current trends.
 

In the next fixed line regulatory review—TAR 2026—Ofcom is likely to maintain light regulation on Openreach’s pricing levels, while also maintaining strict restrictions on its pricing structures, which both help altnets. 

On other matters, none of the interested parties (Openreach/altnets/ISPs) look like getting exactly what they want, but by and large the industry will likely get what it needs—regulatory stability with a broadly pro-investment slant.

The next TAR in 2031 is likely to be more dramatic, but by our estimates, even a full return to cost-based charging will not result in significant wholesale price cuts, which is likely to be a relief to longer term investors in BT and the altnets alike.

Starlink has unveiled its plans for its next-generation satellites, boasting dramatically more capacity than was anticipated, as it aims to bring gigabit speeds to its broadband users.

This rapid growth in capacity poses the risk of a more commercially aggressive Starlink. While this will amplify its impact on the broadband market, it remains a somewhat niche consumer proposition but with additional B2B appeal.

Amazon's Kuiper is gearing up to begin launching its own satellites. While its target of introducing service later this year is likely to slip, Kuiper will bring an important peer competitor to Starlink, and will be the first time that Amazon's retail and marketing heft enters the UK connectivity market.