What happens to my internet during a power cut?

The answer

The router and the provider's box at your home, such as the ONT on a fibre line, both need electricity, so the connection usually stops during a power cut unless they are on a back-up supply. A small battery unit designed for routers can keep them running for a while. Check the power requirements of your devices before buying one and ask the provider whether their equipment works with such units. A mobile hotspot plan is a useful fallback for outages.