Current meters display the amount of energy used but not the cost

Energywatch said the "smart" meters could calculate consumption costs, allowing consumers to check at a glance how much they were spending.

It said the government should ask the industry to adopt the new technology.

The call came on the day British Gas and Scottish Gas price rises of 14.2% came into effect.

Graham Kerr, of Energywatch Scotland, said smart meters could help consumers reduce their costs, promote energy-efficient behaviour, and help prevent vulnerable households getting into debt.

Half-hourly readings

"The paucity of information given to consumers makes it difficult for them to monitor and manage energy costs," he said.

"Smart meters giving half-hourly readings would change this dramatically.

"What more incentive would you need to leave bad habits behind if you had to sit and watch your energy bills go up every 30 minutes?"

Reduce complaints

Energywatch says the changeover would cost suppliers about �85m extra a year. The meters would lead to more accurate billing, leading to fewer complaints and lower costs.

It is still very much worth switching - there are still savings to be made Ofgem, industry regulator Save money switching suppliers

It says suppliers would also save money by being able to read the meters remotely, rather than having to send someone to do so.

The price increases from British Gas and Scottish Gas were announced on 9 September and take effect on Monday.

They are the latest in a series of price rises from all energy suppliers, stretching back to the start of 2004.

Higher prices

Since the start of August more price increases have also been levied on customers of Powergen and EDF - which owns London Energy, Sweb and Seeboard.

The firms have blamed the high price of oil which has risen by 50% in the past 12 months.

They say this has increased the wholesale price of gas imported from the continent, leaving them with no choice but to recover most of the cost from their customers.

Higher domestic prices have already prompted millions of households into saving money by switching suppliers.