FTTC vs FTTP vs cable: what actually determines your broadband speed (UK)

Broadband Provider — Fri, 13 Nov 2026 07:23:07 +0000

TL;DR: In the UK, the biggest factor in your broadband speed is the physical type of connection. On FTTC, a copper line runs from a street cabinet to your home, and the further you are from that cabinet the slower it gets. With FTTP (full fibre), fibre runs all the way to your home, so distance stops mattering. Cable is Virgin Media's coaxial network. After that, peak-time load on shared parts of the network, your router and Wi-Fi, and the device you test on decide how much of that speed you actually see. Most "my broadband is slow" problems are in the last few metres, not the last few miles.

If you've ever tried to work out why a "fibre" connection tops out at 60 Mbps while a friend's does 900, this is for you.

The three access technologies

FTTC: fibre to the cabinet, copper the rest

Fibre runs from the exchange to the green street cabinet. From there, your existing copper phone pair carries the signal into your home using VDSL2. On the Openreach network, FTTC tops out at 80 Mbps down and 20 Mbps up.

The key constraint is signal loss over distance. A VDSL2 signal fades as it travels along copper, and the higher frequencies that carry the most data fade fastest. So line length between cabinet and socket largely sets your sync speed (the rate your modem agrees with the cabinet). Two houses on the same street can sync at very different rates. Old joints, corroded wiring and poor internal extension wiring all add noise, which lowers it further.

From a debugging angle, FTTC is the only one of the three where the physical length of your line is a first-order variable. If your router shows a sync speed well below 80 Mbps, no amount of Wi-Fi tuning will get you past it.

FTTP: fibre to the premises ("full fibre")

Fibre runs all the way to an optical network terminal (ONT) inside your home, and your router plugs into that. Most UK full fibre uses a passive optical network (PON). One fibre from the exchange is split, using passive splitters, between a group of homes.

GPON carries roughly 2.5 Gbps down and 1.25 Gbps up, shared across everyone on that split.
XGS-PON raises that to about 10 Gbps in both directions, and several UK networks are moving to it.

Two things follow from this. First, distance is effectively irrelevant within normal PON reach, so a home at the end of the road gets the same tier as one next to the cabinet. Second, the shared part is sized well above any single package. That's why a 900 Mbps plan on full fibre usually delivers close to its tier on a wired test. On full fibre, the package you buy, not your line, is normally the limit.

Upload is the other big difference. FTTC caps upload at 20 Mbps. Full fibre plans commonly offer far more, and some are symmetrical (the same upload as download). If you push builds, back up a NAS or stream, that matters more than another 100 Mbps of download.

Cable: Virgin Media's coaxial network

UK "cable" broadband means Virgin Media's hybrid fibre-coax network. Fibre runs to the street, and coaxial cable carries it the final stretch using DOCSIS 3.1. Coax doesn't suffer the same distance problem as a copper phone pair, so cable can deliver around gigabit download speeds. Upload speeds on cable have historically been much lower than download.

Cable capacity is also shared among homes on the same segment, so busy evenings can show more variation than on a well-provisioned PON. Virgin's network sits entirely separate from Openreach's, so whether you can get cable is a separate question from whether you can get FTTC or FTTP.

Why "fibre" in an ad doesn't tell you which one you have

In the UK, "fibre broadband" has long been used for FTTC as well as full fibre, because part of the route is fibre. "Full fibre" is the phrase to look for if you want FTTP. When in doubt, check by address rather than by product name. Here's how to check which line type your address can get.

The speed in an ad is also an average. UK advertising rules require headline speeds to be what at least half of customers on that package get at peak time (8pm to 10pm). So the number is a median, not a guarantee.

The rest of the chain

Once the access network is accounted for, these are the usual bottlenecks, roughly in order of how often they matter:

Wi-Fi. The most common limit by far. Distance, walls, 2.4 GHz congestion, older client devices and a router stuck in a cupboard can each halve your throughput. A 900 Mbps line tested over Wi-Fi in a back bedroom tells you about your Wi-Fi, not your line.
The test device. A laptop with a 100 Mbps Ethernet port, an old Wi-Fi chipset or a busy CPU will cap results. Gigabit tests need gigabit-capable hardware end to end.
Peak-time contention. Shared capacity (cable segments, backhaul, the provider's core) gets busier in the evening. A wired test at 3am versus 9pm shows how much this affects you.
Internal wiring (FTTC only). Extension sockets and long internal phone cables add noise. Testing from the master socket rules this out.
The far end. A download is only as fast as the server sending it. Speed test servers are well provisioned; a random file host may not be.

And keep units straight. Packages are sold in megabits per second (Mbps), while download managers often show megabytes per second (MB/s). Divide Mbps by 8: a 500 Mbps line peaks at about 62.5 MB/s before overheads.

Throughput isn't the whole story for gaming or video calls either. Round-trip time and jitter often matter more, which is why it's worth understanding latency versus raw speed before paying for a faster tier.

A sane way to measure

Plug a capable machine into the router with Ethernet and close everything else.
On FTTC, note the router's reported sync speed first. That's your ceiling.
Run tests at a quiet time and again at peak (8pm to 10pm), on more than one day.
Only then test over Wi-Fi, in the rooms you actually use. The gap between wired and wireless is your home network problem to solve.

What the market looks like right now

In Broadband Provider's daily snapshot of live UK deals on 13 November 2026, 110 of the 377 packages we track advertised 900 Mbps or more. 50 were at 80 Mbps or below, the FTTC ceiling. Where full fibre has reached you, the speed tier is mostly a pricing decision rather than a technical one. If you want to see what that costs, you can compare full fibre packages side by side.

FAQ

Is FTTC "real" fibre?
Partly. It's fibre to the street cabinet and copper from there to your home. Full fibre (FTTP) is fibre all the way.

Why is my 900 Mbps connection only showing 300 Mbps?
Usually Wi-Fi or the test device. Test wired on gigabit hardware first.

Does distance from the exchange affect full fibre?
Not in any way you'll notice within normal network reach. Distance mainly matters on FTTC's copper section.

Julian Glover is the editor of Broadband Provider. Independent UK broadband comparison: live deals scored on speed, price and contract terms, plus plain-English guides. https://broadbandprovider.co.uk

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