Pensioners have warned the second British Gas price hike in a year could threaten their health and cause even more financial hardship.

Centrica, which owns British Gas, plans to raise the bills of its 10.7 million customers by 12.4 per cent from September.

The rise comes just four months after the energy giant increased prices by 22 per cent.

The company said "unprecedented high wholesale energy costs" had made the price increases necessary.

The firm's electricity customers will also face a 9.4 per cent increase in their bills from September.

But elderly people attending the Abingdon Day Centre yesterday hit back angrily saying their health was being put at risk.

Henry Leach, 85, from Sutton Courtenay, said: "People just end up turning their heating down because they are worried about the cost.

"I am being forced to use my microwave rather than my oven, just to save on energy costs.

"Everything is going up - the council tax, electricity, but there is no extra income for us pensioners.

"I'm worried that it's only a matter of time before electricity goes up again too."

Abingdon Day Centre manager, Frances Lee, said everyone had been shocked by the news of the increase.

"They all feel very vulnerable," she said.

"Many tell you they turn their heating down, or just heat one room.

"One of our clients said she would wrap herself up and bring herself down here to keep warm, or even spend the day in the library."

News of the fresh round of price rises comes as British Gas reported record losses of £143m during the first six months of the year.

The company's price hike in March prompted some customers to switch supplier and, six months later, 432,000 energy accounts had been lost.

Among those who looked for and found a cheaper option were Winsome James, 68, from Rose Hill.

Mrs James, who lives alone and is disabled by damaged hips, said: "I had been with British Gas for years, but it was becoming such a struggle to heat my flat, I swapped my account to Southern Electric, in April.

"But even after all those years of paying my bills on time, British Gas still let me down, because I was £45.18 in credit when I left and they still have not paid me what they owe me.

"Living on a limited income, like many elderly people, I am aware of what my heating is costing all the time and that is wrong.

"I fear the price increases will mean more elderly people choose to reduce their heating even further and more people will die."

Mary Daniel, the chief executive of Age Concern Oxfordshire, said: "Pensioners living on a low, fixed income will struggle to pay these inflation-busting bills.

"Energy companies should do everything they can to protect vulnerable groups, such as pensioners, from price increases.

"We urge older people to consider shopping around for their energy provider. There are many established companies offering competitive rates for fuel costs.

"Older people should also check they are receiving all the benefits they are entitled to."

Age Concern offers free advice on 01235 849400 or call 0800 009966 for a free factsheet.

* The latest price hike from British Gas came as Scottish & Southern Energy (SSE), which owns Southern Electric, stuck by a pledge to leave prices unchanged this year.