FURIOUS gas customers claim they are being misled by an advertisement promising to freeze their fuel bills.

A leaflet sent to homeowners by Npower, promises to freeze customers' bills for nine months if they call a special phone line.

It asks customers of Northern Electric and Gas - the supply company owned by Npower - to take advantage of the price freeze to avoid forthcoming gas increases.

But some customers say the advertisement is misleading.

One customer, who did not want to be named, contacted the company and was told his bill would have to increase before the price freeze applied.

The man, from Darlington, said: "I was told that, to qualify for their price freeze, I would actually have to agree to paying more for my gas so that they could bring the amount charged by Northern Electric and Gas into line with their parent company, National Power.

"She also said that, if I agreed, it would protect me against any further price rises this year.

"I thought the leaflet they sent to customers was totally misleading. It was quick to promote price freezes but it failed to mention you had to pay more to get one."

A spokeswoman for Npower North-East said: "The tariffs are slightly different in different areas. It does involve a slight cost increase for Northern Electric and Gas customers, but we wanted the price freeze to apply to all customers.

"It is to guard against any other possibility of price increases and it is a genuine offer."