Smart meters will allow energy firms to introduce "surge pricing", one of Britain's biggest gas and electric providers has admitted for the first time.

New deals which will mean the price of energy fluctuates every half an hour will be introduced as soon the energy regulator has given them the green light, Scottish Power told the Telegraph.

The controversial tariffs rely on smart meters and will radically change the way households consume energy, leading to them paying more for watching television, charging gadgets and running the washing machine during popular times such as in the mornings and evenings.

Energy prices for customers on such tariffs will peak on special events like Christmas Day and Easter, when millions of households are all using ovens at the same time.

But the hope is that a new wave of smart gadgets that can talk to smart meters will end up reducing households' bills in the long run, by making the system more efficient.