Battery lights vs mains LED bulbs: What's cheaper?

As some shoppers swap mains bulbs for battery lights, is money really being saved?

All Things Money financial blogger Ola Majekodunmi goes through the numbers - in under a minute.

Produced by Jamie Moreland and the Video Formats team.

This video has been optimised for mobile viewing on the BBC News app. The BBC News app is available from the Apple App Store for iPhone and Google Play Store for Android.