What is full fibre, and when is part-fibre enough?

Full fibre is a description of the line, not a badge for a fast advert. Fibre optic cable carries the service all the way to the premises. That is FTTP: fibre to the premises. Everything else that still says fibre may be stopping short, usually at a street cabinet, and finishing the journey on copper.

Three lines people mix up

FTTC, fibre to the cabinet, is the older part-fibre service. Fibre runs to a cabinet in the street. The last stretch is a copper pair. Distance from that cabinet still matters. Two houses on the same estate can see different speeds on the same advertised product because the copper is not the same length.

FTTP removes that copper tail. The optical network terminal, a small box, sits in the home and the fibre ends there. Upload is often closer to download than on part-fibre, but only on the tier you actually buy. Full fibre is not one speed. It is a way of delivering several speeds.

Cable is a third thing. Much of it was built for television and later carried broadband. It can be very fast. It is still not full fibre, and a switch onto or off it can mean a different engineer, a different socket and a different failure mode. Comparing a cable product with an Openreach FTTP product is allowed. Calling them the same technology is not.

The network and the retailer are not the same

Openreach builds a large share of the UK’s full-fibre plant and wholesales it. CityFibre, and other alternative networks, build their own streets. Virgin Media’s cable plant is separate again. You usually pay a retailer: BT, Sky, Vodafone, a digital brand, or the network’s own brand. The bill, the router and the call centre belong to the retailer. The trench belongs to the network.

That split matters when something fails. A slow Wi-Fi complaint is not a network fault. A dark optical terminal might be. If two retailers use the same network at your address, switching between them may not need a new fibre pull. If they do not, it might. The only honest check is the one the provider runs for that address, not a map of the borough.

What an install usually involves

A first full-fibre install is a visit, not a setting in an app. Someone may need to bring fibre from the street or from a riser in a block, agree where the box goes, and test the light. Flats are harder when the building owner has not agreed access. A rented house can need the landlord’s permission for drilling. None of that is settled by a postcode looking “gigabit ready” on a national page.

• Ask which network the product uses, not only the logo on the advert.
• Ask whether an engineer is required, and what happens if you are out.
• Ask where the equipment will be fitted, and whether you can keep using the old line until the new one works.
• If you are already on full fibre, compare the contract. Do not pay for an upgrade you already have.

When part-fibre is enough

A household that browses, streams on one screen and rarely uploads large files can be well served by a stable part-fibre or mid-tier cable product. The reasons to want full fibre are more specific: upload for video calls and backups, a short or unreliable copper tail, or a contract that is worse than a full-fibre offer you can actually order.

Speed on a poster is not that test. Neither is a neighbour’s install. OneTouchSwitch can explain the difference and point you at a published offer. It cannot tell you the fibre is orderable at your door until the provider confirms it.