Know what your phone uses
Digital landlines generally depend on a powered router. A corded handset plugged into a router is still dependent on that router; simply buying a corded phone will not solve a digital-line power problem.
Ask your provider now
Tell your phone provider if you depend on the landline, have no working mobile or have unreliable mobile coverage. Ofcom explains that providers must offer eligible people a free backup solution to make emergency calls during a power cut, lasting at least one hour.
Include connected equipment
If you have telecare or a personal alarm, ask both the alarm service and phone provider how it behaves when the electricity or broadband fails. Test only in the way the provider recommends. Keep their support numbers on paper.
Have a household contact plan
Charge phones before forecast severe weather and keep a suitable power bank. Mobile networks can also be disrupted, so agree how to check on someone nearby if calls fail and it is safe to visit.
Ofcom: your landline is going digital ↗
Check the linked guidance for updates. Follow local instructions during a real incident. This site does not provide live emergency information.