BT on CityFibre: what the TalkTalk rescue buys

Until now, BT Group's consumer brands, BT, EE and Plusnet, have sold broadband only over Openreach. With TalkTalk, BT Group can sell full fibre over other companies' networks for the first time. On CityFibre alone, 1.38 million of the premises it can now reach have no Openreach FTTP today.

BT completed the purchase of TalkTalk's consumer business and its wholesale arm, PlatformX (PXC), on 5 October 2026. It bought them out of administration on a debt-free basis. BT puts the cash impact in FY27 at around £400m. That figure includes a trading loss of about £60m for the rest of the year and about £100m owed to Openreach that will now not be paid. The deal covers 1.5 million retail and 1 million wholesale customers. Digital Secretary Lisa Nandy has issued a Public Interest Intervention Notice, and the CMA must report to her by 19 October. Until then BT and TalkTalk are operating separately.

This piece looks at the networks.

BT's first footprint off Openreach

In Point Topic's data, BT, EE and Plusnet sell only over Openreach. TalkTalk sells over Openreach too, but also over CityFibre, Community Fibre and Freedom Fibre. Across those three networks, TalkTalk can sell to about 5.7 million premises.

Most of that is CityFibre. TalkTalk can sell on CityFibre to over 4 million premises, out of CityFibre's 4.26 million footprint. About two-thirds of those premises (2.64 million) already have Openreach FTTP as well. There, BT could move a TalkTalk customer from CityFibre onto its own network whenever it chose.

The other third is where it gets interesting. About 1.38 million premises reachable through TalkTalk on CityFibre have no Openreach FTTP today. About 0.33 million of them have no Virgin Media network either, including nexfibre. Adding Community Fibre and Freedom Fibre, BT Group's full-fibre reach rises from about 23.0 million to 24.8 million premises, an increase of about 8%, without building anything.

TalkTalk on CityFibre	Premises	Share
Openreach FTTP also present	2.64m	66%
No Openreach FTTP	1.38m	34%
No Openreach FTTP, Virgin Media or nexfibre	0.33m	8%

BT now has a reason to sell on CityFibre where Openreach hasn't built. How long that lasts depends on Openreach's build, and the deal itself may change Openreach's priorities. A group that can already sell to a customer over CityFibre has less reason to build its own network in the same streets, or more reason to build there quickly and move the customer across. It also depends on the terms of TalkTalk's CityFibre contract, which are not public: minimum volumes, notice periods and any exclusivity.

Where the gap is

Subscribers only: a region-by-region breakdown of the 1.38 million premises without Openreach FTTP, and of the 0.33 million with no Virgin Media or nexfibre either, with chart and table. Subscribe or sign in

What CityFibre loses, and what it has already lost

CityFibre passed 1 million connections in Q2 2026 on Point Topic's Global Broadband Statistics (GBS) data, adding 85,000 in the quarter after 67,000 in Q1 (CityFibre announced the milestone on 3 June). The Telegraph reported in June 2025 that around 150,000 TalkTalk customers were on CityFibre. Part of that base has already moved. Rise Fibre, which took about 120,000 TalkTalk customers in August, also sells on CityFibre, so some of those lines stay on the network under a different brand.

From completion, and subject to the CMA's review, what changes is who owns the rest. CityFibre's main national retail partners are TalkTalk, Sky, Vodafone and Zen. One of them now belongs to the parent company of CityFibre's direct competitor.

The failing-firm test

BT presents the deal as a rescue, so the CMA's assessment is likely to turn on the failing-firm test. The test asks three questions. Would TalkTalk have exited the market without the deal? Was there a less anticompetitive buyer? And what would have happened to its customers and network routes if it had exited?

1. Would TalkTalk have exited? The case is strong. On GBS data, TalkTalk's residential base fell from 3.15 million in Q3 2024 to 2.57 million in Q1 2026 and an estimated 1.80 million in Q2 2026, as TalkTalk offloaded customers to other ISPs and lost others to churn. After the transfers of about 120,000 customers to Rise Fibre in August and 13,500 to Fleur Telecom in September, we estimate the remaining consumer base at 1.5–1.6 million, in line with BT's figure of 1.5 million. The group went into administration, the business was loss-making, and BT describes the deal as following an unsuccessful sale process.

2. Was there a less anticompetitive buyer? This is the contested question. Bids were reported from Epiris (working with PXC chairman Tom O'Hagan), Octopus via Fern Trading, and Telecel for PXC, and from Opus Broadband and VodafoneThree for the consumer business. An exclusivity period for the consumer business lapsed without a deal. A split sale, with the consumer business and PXC going to different buyers, was the route the sale process tried. The two businesses' dependence on each other made that hard to achieve, and BT called its deal the only viable option. The CMA will need to test that claim. What BT gains is clear: about 1.8 million premises of full fibre that Openreach does not reach today, and a choice it did not have before: build Openreach FTTP there, or keep selling over a competitor's network.

3. What if TalkTalk had exited? Most TalkTalk customers are on Openreach, so Openreach would keep most of those lines whichever ISP they moved to. The networks that lose are CityFibre, Community Fibre and Freedom Fibre, each of which would lose a national retail partner. Seen this way, exit would have cost the altnets more than Openreach. The deal keeps TalkTalk's altnet routes open, but puts them under BT's control.

If the CMA accepts the rescue case but has concerns about part of it, the remedies to watch are conditions on PXC, up to and including a sale, and commitments on how BT treats TalkTalk's customers on CityFibre and the other altnets.

The contrast with nexfibre / Substantial is sharp. On 2 October the CMA provisionally found that nexfibre's purchase of Substantial (Netomnia, brsk and YouFibre) may substantially lessen competition in wholesale broadband. The CMA's view was that, without the deal, CityFibre would probably have bought Substantial and wholesaled the network to ISPs including Sky and VodafoneThree. Days later, the incumbent has bought an ISP and its routes onto CityFibre, through a rescue. That contrast is likely to shape how the industry reads the CMA's decision on 19 October.

How we count

• Premises: all premises in postcodes where a network is present. This somewhat overstates reach at the edges, and applies equally to every network compared here.

• Virgin Media: Virgin Media's cable (DOCSIS 3.1) and RFoG networks, and its XGS-PON full fibre: the Project Mustang upgrade of its own network, plus nexfibre.

• Reach: where TalkTalk sells over a network, according to Point Topic's data on which ISP sells over which network.

Caveats

• Footprint figures are Point Topic estimates from our Unit Postcode (UPC) dataset (current snapshot). TalkTalk's reach on CityFibre may be understated in some towns CityFibre has added since 2024.

• Subscriber figures are from Global Broadband Statistics (GBS), latest quarter Q2 2026. TalkTalk's Q2 2026 figure is a Point Topic estimate; lines it offloaded to ISPs not tracked individually sit under "Other" in GBS. BT's 1.5 million retail figure is a company number.

• PXC's own wholesale network, and how it aggregates other altnets, is not yet modelled separately in our data. This piece covers TalkTalk's retail routes only.

Data: Point Topic Unit Postcode (UPC) footprint estimates, Global Broadband Statistics (GBS) subscribers. Analysis October 2026.