Ofgem sign
Media playback is unsupported on your device
Video

Ofgem: Money is deeply buried in 'big six' accounts

The "big six" energy companies have been told to hand back more than £400m owed to customers.

Credit left in customer accounts when people and businesses move or switch suppliers has accumulated over the past six years, Ofgem said.

Ofgem director Philip Cullum told BBC Breakfast the watchdog's action "reflected the significance of the issue".

Go to next video: Energy firms told to trade fairly