British consumers are being warned that they will end up paying much more for pork if the financial crisis gripping the country's pig farms is not addressed. More than two-thirds of pig farmers say they will be out of business within two years due to the soaring cost of feeding their stock.

The price of wheat and other staple crops has almost doubled over the past year, resulting in an increase in the cost of animal feed. As feed is responsible for the majority of costs involved in pig-keeping, the rise has had a significant effect on Britain's 2,000 commercial pig farmers.

The major supermarkets have so far kept a lid on increases in the price of pork, which has been good news for consumers, but this has squeezed pig farmers, who have seen their profits collapse. There are now warnings that such a measure by the supermarkets has brought only short-term savings to the consumer as pig farmers say they are on the brink of leaving the industry.

Pig farmers report the situation is worse than in 2007, when food inflation eroded their profits and the size of Britain's swine herds fell by more than 7%. The industry bounced back in 2009 following a tightening of supply, caused by fewer pigs entering the market, and favourable exchange rates. But the manipulation of commodity prices by hedge funds, crop failures attributed to climate change, and Russia's decision to restrict wheat exports have seen animal feed costs rise considerably.

Barney Kay, general manager of the National Pig Association, called on supermarkets to give a better deal to pig farmers as they tried to weather the latest pressures affecting the industry.

"At the moment, supermarkets and most processors are making large profits – but pig farmers are losing around £20 on every pig they sell," he said.

The NPA claims more than 80% of British pig farmers are losing money, and 70% say they will have to quit pigs in the next two years if they do not get a better price from supermarkets.

New EU welfare rules that come into force in 2013 are predicted to increase European demand for British pork, which meets stringent guidelines. Kay predicted that if British pig farmers went out of business before then, it would result in a significant increase in the price of pork for consumers.

The NPA has launched a multimillion pound advertising campaign to remind shoppers to buy high-welfare British pork, bacon and sausages. Roadside fields are being used to display 15ft banners promoting British pork. All the banners display British farming's Red Tractor symbol, which shows food has been produced on British farms to agreed welfare, environmental and safety standards.

"The aim of this campaign is to persuade shoppers to make an extra effort to choose British rather than anonymous lower-welfare imported pork," Kay said.

Pig farmers are planning a march on Downing Street next month to draw attention to the crisis.