How to Keep Broadband Working in a Power Cut UK [2026]: Backup Options

The lights go out in a winter storm, and so does your Wi-Fi — and with it, your landline. Since the UK switch to digital landlines, home phones plug into the router, so no power means no phone unless something is backing it up.

This is based on Ofcom guidance and manufacturer specifications. I haven't tested these products in my own home.

Keep the router (and the fibre box on the wall, if you have one) running from a battery. If you rely on the landline — for example, for a telecare alarm — speak to your provider first. For everyone else, a small UPS or a portable power station does the job.

Ofcom says that unlike some old corded analogue phones, a digital phone will only work in a power cut if it has a battery backup. Your router, and the Openreach or other fibre box if you have full fibre, both need mains power.

Ofcom's guidance requires providers to offer a solution that gives at least one hour of power resilience to customers who need it to contact emergency services in a power cut, and this must be free for those who need it. Providers must also identify and support vulnerable customers, including people who use telecare. If that's you, ask your provider directly.

1. Your provider's battery backup unit. The first call if you rely on the landline.

2. A small UPS (uninterruptible power supply). It sits between the wall socket and your router, switching to battery instantly when the power fails. Schneider Electric's APC Back-UPS BX950MI, for example, has six IEC C13 outlets — you'd need IEC-to-UK socket leads for UK plug adapters. Check outlet type before buying.

Compare router UPS units on Amazon UK

3. A portable power station. More capacity, and it can also charge phones and run lights. Compare options in our best portable power stations guide.

4. A mini DC UPS. Small battery packs made for routers. Match the voltage and plug to your router's power adapter exactly.

Divide the battery's usable watt-hours by the power your router and fibre box use. A router and fibre box together often use somewhere around 10–20W, but check the labels or measure with a metering smart plug. From 30 years in electrical engineering, my rule is to size for the longest cut you'd realistically face, then add a margin — batteries never deliver their full rated capacity.

• Ofcom: Protecting customers during the migration to digital landlines

• Ofcom: Access to emergency organisations in a power cut

• Ofcom: The future of landline calls

• Schneider Electric: APC Back-UPS BX950MI

*Researched October 2026 from manufacturer specifications, official guidance and independent UK sources; we do not test products in our own home. Prices change often — always check the current price before buying. This article contains affiliate links — see our disclosure.*