Massive rises in the cost of heating oil could see elderly and vulnerable people in Norfolk freeze to death because they can't afford to stay warm.

Thousands of people in rural areas rely on oil for their heating and have been stunned as the price rocketed by more than 50pc in just four weeks.

Now agencies fear that pensioners will lose their lives because they cannot afford to put oil in their tanks and are too afraid to use electric heaters instead because of the cost.

'We are scared that people will die over this period,' said Lin Mathews, of Norfolk Age UK.

'It is dreadful. Older people just cannot find this extra money and they are vulnerable when it is so cold. When you have oil heating there is no prior warning about increases like there are with gas or electricity. You don't find out until you phone,' she said

Worried pensioners are already calling the organisation's advice lines not knowing how they can afford to keep warm.

'All we can do when the issue is money is to suggest they go to good people to borrow from, like credit unions, but it is dreadful that our older people are having to do this.'

Consumers using gas or electricity for their heating have regulatory bodies such as Ofgem to complain to about pricing, but oil-users have no such advocates and are left to pay the bills - a situation Norfolk Age UK would like to see rectified.

'In built-up areas people are OK, they have a choice and can switch suppliers. Many of them don't realise the cost of keeping warm when you rely on oil and there is no-one to speak up or complain to.'

Four weeks ago heating oil was costing around 45p a litre for the minimum 500-litre order, but this week the price hit 70p - a rise of more than 50pc.

'I think it's shocking and I think that if companies are going to do this, the elderly should look at using other forms of heating if they can.

'It's frightening for elderly people and I am surprised that peoples' consciences aren't being pricked by this,' said Edith Pocock, president of the Norfolk and Norwich Pensioners Asssociation.

A 500-litre delivery of oil should last the average home between four and six weeks, depending on usage, but vulnerable people who need full-time heating are likely to use much more.

There are also accusations of profiteering by oil companies during the extreme cold.

'The dramatic increases in oil prices we have seen recently can, in my view, only be explained by blatent profiteering, perhaps driven by financial speculation on the oil price. Whatever the reason this behaviour is socially completely unacceptable and it adversely affects some of the most vulnerable members of our society,' said a letter to Mid-Norfolk MP Keith Simpson from resident Martin Wootton.

He said he was angry at the sudden, sharp increase in prices which would hit the most vulnerable members of society.

'I am not prepared to sit back and do nothing about this situation. I insist that this subject is raised at the high levels of government,' he added.

Doug Rutherford, of Buxton, near Norwich, said his oil bill for a 2,000-litre delivery had climbed from �814 in February 2009 to �1,260 this week.

'Nobody seems to have the power over the oil companies and they are doing what they want,' he said.

The county's rural residents are being hard hit as the hike in heating oil prices is matched by increasing costs for petrol and diesel.

The situation is set to get worse, with predictions of another big freeze heading towards Norfolk and the addition of around 3p a litre on the price of petrol in the first week of the 2011 when VAT and duty increases hit the pumps.