Consumers in Aberdeen, Birmingham, Brighton, Newcastle and Southamption will be able to choose their suppliers from January, according to the Office of Electricity Regulation.

It will bring the total number of consumers who can now shop around to 9m.

Offer says more competition has led to lower bills

Director General of Electricity Supply Stephen Littlechild said: "Competition is giving customers real choice and bringing benefits.

"Over 165,000 customers across the country have already changed supplier during the first three months, and over one million have signed up to do so in due course

"Changing supplier is easy; no new meters or new cables are required. Prices vary from area to area, but savings of around £35 to £40 on an average bill of £275 are on offer to domestic customers.

"So our message is simple. Shop around, worthwhile savings are to be found."

Customers can get further information by ringing Offer's freephone helpline on 0800 451 451

The first group of companies to open up their markets were Eastern Electricity, Manweb, ScottishPower and Yorkshire Electricity back in September.

Midlands Electricity and Seeboard started opening their markets to competitive supply in October with Northern Electric and Scottish Hydro-Electric following suit in November.