The short version
General information, not advice
- Since 16 September 2024, providers have to say what kind of line they’re selling: full-fibre, part-fibre, cable or copper. “Fibre” on its own isn’t allowed.
- Part-fibre slows down the further you live from the street cabinet. Full fibre doesn’t.
- Upload speed matters for video calls and backups, and part-fibre lines are much weaker on it.
- If a fast line feels slow, the problem is usually the Wi-Fi, not the line.
Explained in pictures
Full fibre and part fibre
Source: Ofcom guidance on broadband technology terms, checked 30 September 2026. Illustrative; speeds are in the guide below.
Showing both connections. Pick a step to inspect it.
What the words on the advert mean
For years almost every package was sold as “fibre”, including ones where the fibre stopped at a green cabinet at the end of the street and the last few hundred metres ran over the old copper phone line. Ofcom decided that was ambiguous. Since 16 September 2024, providers have had to describe the line itself, in plain words, before you buy. Full-fibre means fibre runs all the way into your home. Part-fibre means fibre to the cabinet and copper from there. Cable is the Virgin Media-style coaxial network, and copper is the old phone line all the way. If a contract summary uses one of those words, you know what you’re getting.
Why distance matters on part-fibre
Copper loses signal over distance, so on a part-fibre line two houses on the same street can get very different speeds. The house next to the cabinet gets close to the advertised figure; the one at the far end of a long road gets noticeably less. Full fibre doesn’t have that problem, because light down a fibre barely weakens over the distances involved. It’s also why a provider’s speed estimate is tied to your exact address rather than your postcode.
How much speed you actually need
Less than the adverts suggest. Netflix recommends 15 Mbps for one 4K stream and 5 Mbps for Full HD. Add up what happens at once in your house at the busiest time, usually early evening, and leave some room.
| At the same time | Rough total |
|---|---|
| Two people streaming in HD, one browsing | About 15 Mbps |
| Two 4K streams and a video call | About 35 Mbps, plus upload for the call |
| A family of five, all online in the evening | Check what each person does; many households need well under 100 Mbps |
Streaming figures: Netflix Help Centre, “Internet connection speed recommendations”, checked 26 September 2026. The totals are simple sums of those figures, not measurements.
Upload, the half nobody advertises
Download is what comes in: streaming, web pages, updates. Upload is what goes out: your face on a video call, photos backing up to the cloud, a big file sent to work. Part-fibre lines give far less upload than download, while many full-fibre packages give much more, and some give the same speed both ways. If you work from home, check the upload figure before the download one.
When a fast line feels slow
The speed on your phone is set by the slowest link between the street and your hand. An old router, a router in a cupboard at one end of the house, thick walls and an old phone all cut it down, however fast the line is. Before paying for a faster package, plug a laptop into the router with a cable and run a speed test. If that’s close to what you pay for, the line is fine and the Wi-Fi is the problem: move the router somewhere central and high, or add mesh points. If the cabled test is slow as well, it’s worth a call to your provider.
Sources, checked 26 September 2026: Ofcom: improving broadband information for consumers (statement, December 2023) · Netflix: internet connection speed recommendations.Switch4Good Limited is a commercial business and not a charity. General information, not advice.
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