The short answer: ADSL uses your copper phone line and tops out at around 24 Mbps download. Standard fibre (FTTC) uses a fibre cable to your street cabinet, then copper to your home, giving 35–80 Mbps. Full fibre (FTTP) runs fibre all the way to your home, giving 100 Mbps to 1 Gbps. If fibre is available at your address, there is no good reason to stay on ADSL.
ADSL: copper all the way
ADSL (Asymmetric Digital Subscriber Line) works by sending broadband data over the same copper wire as your phone line. The technology is old, dating back to the late 1990s, but it covers virtually the entire UK — around 99% of premises.
The fundamental limitation of ADSL is the copper wire itself. Copper degrades signal over distance. The further your home is from the telephone exchange, the slower your connection. Someone 200 metres from an exchange might get 20 Mbps. Someone 2 kilometres away might get 5–8 Mbps. And at the far end, distances above 5 km, speeds can drop below 1 Mbps.
ADSL also gives you much less upload bandwidth than download. A typical ADSL connection might be 10 Mbps down and 1 Mbps up. That 1 Mbps upload makes video calls unreliable and file uploads frustratingly slow.
FTTC: fibre to the cabinet
FTTC (Fibre to the Cabinet) improves on ADSL by replacing the copper between the telephone exchange and the green street cabinet with fibre optic cable. The final stretch, from the cabinet to your home, still uses copper — but this stretch is much shorter, typically 50–300 metres. Shorter copper means better speeds.
FTTC is marketed as "fibre broadband" but is more accurately described as part-fibre. It gives typical download speeds of 35–80 Mbps and upload speeds of 10–20 Mbps. Speed still depends on your distance from the cabinet, but the effect is smaller than with ADSL. FTTC covers around 97% of UK premises.
FTTP: fibre all the way home
FTTP (Fibre to the Premises, also called full fibre) replaces the copper entirely. A fibre optic cable runs from the exchange all the way into your home, where it connects to a small box called an ONT (Optical Network Terminal). You plug your router into the ONT.
Because there is no copper, speed does not depend on distance. You get the same speed whether you are next door to the exchange or a kilometre away. FTTP also offers symmetrical speeds — your upload speed matches your download speed, which makes a significant difference for video calls and file sharing. Coverage is currently above 70% of UK premises and is growing rapidly.
Side-by-side comparison
| ADSL | FTTC | FTTP | |
|---|---|---|---|
| Technology | Copper phone line | Fibre to cabinet, copper to home | Fibre all the way to home |
| Typical download | Up to 24 Mbps | 35–80 Mbps | 100 Mbps – 1 Gbps |
| Typical upload | 0.5–2 Mbps | 10–20 Mbps | 50–500 Mbps |
| Speed varies by distance? | Yes, significantly | Yes, but less so | No |
| UK coverage | ~99% | ~97% | 70%+ |
| Typical monthly cost | £20–25 | £25–35 | £28–45 |
| Engineer visit needed? | Usually no | Usually no | Yes (one-off) |
Who should be on each type?
ADSL
ADSL is the right choice only if FTTC and FTTP are not available at your address. If you are a single person doing light browsing and email, ADSL speeds may be adequate — but even then, FTTC is worth having if available. If you are on ADSL and your speeds are below 10 Mbps, check whether you are eligible for the Universal Service Obligation, which gives you the right to request a faster connection.
FTTC
FTTC is the right choice if full fibre is not yet available at your address. It gives more than enough speed for streaming, video calls and working from home for most households. If you are on FTTC and full fibre becomes available at your address, switching is worth considering — particularly if upload speed is important to you.
FTTP
FTTP is the best option available for most households where it is accessible. The extra monthly cost over FTTC is small, and the benefits — faster speeds, better upload, more reliable connection, no dependence on ageing copper — are real. If full fibre is available at your address, there is no good argument for choosing FTTC instead.
Frequently asked questions
Can I get FTTC or FTTP if I do not have a phone line?
ADSL requires a phone line. FTTC also uses the copper phone line (though you may not need to make calls on it). FTTP does not require a phone line at all — if you want to keep a phone number, it runs over VoIP on the fibre connection. Some FTTC providers offer "broadband-only" packages without a separate phone line rental, but the underlying copper connection still exists.
Why does my FTTC speed drop in the evenings?
Evening congestion (roughly 7–10pm) is common on FTTC because many households in the same area use the internet simultaneously, and the shared infrastructure between the cabinet and the exchange can become a bottleneck. FTTP is less susceptible to this because it has greater capacity. If evening slowdowns are a consistent problem, switching to FTTP or a different provider may help.
Is ADSL being switched off?
The old copper phone network (PSTN) is being gradually retired, with full switch-off targeted for January 2027. ADSL broadband depends on the copper phone line, so it will eventually cease to exist. If you are still on ADSL, check what alternatives are available at your address.