There are more than one million EVs and 670,000 plug-in hybrid vehicles on UK roads, with 23% of London motorists owning one, compared with Plymouth, where only 5% of drivers have a plug-in car.

Time-of-use tariffs charge different prices for electricity at various times of day, making them a good option for electric vehicle owners who charge their cars overnight. Some time-of-use tariffs charge as little as 7p per unit of electricity – less than a third of the current 22p cost on a price-capped tariff.

Despite this potential saving, only one in five households with an electric vehicle (19%) and one in six of those with a plug-in hybrid (16%) are currently on a time-of-use tariff.

Charging an electric vehicle’s 60kWh battery on a price-capped tariff costs £13.42, compared with only £4.20 on the cheapest time-of-use tariff – a difference of £9.22.

Based on the average UK driver’s annual mileage of 7,400 miles, this works out at £552 a year on a price-capped tariff and £173 a year on an EV or time-of-use tariff – an annual saving of £379.

Three-quarters of households (74%) don’t know what a time-of-use tariff is, and two in five (43%) have never heard of one.

Only 4% of households say they are currently on a time-of-use deal like an Economy 7 tariff, which charges less for electricity at night, and just 1% have a specific EV tariff.

Once they understood how a time-of-use tariff worked, nearly three-fifths of households (57%) said they would consider getting one.