Shoppers in the UK have noticed a trend: they're paying more for groceries, but getting the same amount of food they were a year ago. Information from the My Supermarket website - which compares food prices on a daily basis - offers evidence that consumers aren't imagining the increase; according to the site, the overall rise in cost over the past year is 12 per cent, or approximately £750 per year.

The more well-to-do middle class in Britain are barely aware of a change and if they have noticed, they aren't terribly concerned. Poorer areas in Scotland however are starting to worry about the difference. And if various global organizations are right in their predictions that food prices could rise as little as 10 per cent or as much as 50 per cent within the next decade, their concern is not without merit.

Four key factors have been identified as being responsible for the rise in food costs: the skyrocketing cost of oil, climate issues such as the droughts, hurricanes and floods during the past year, a financial boom in India and China, and the significant increase of staple-food commodities such as wheat, maize and soya. The increase of the latter is largely due to the demand for alternative fuel options, most notably ethanol.

Ethanol, a diesel-type fuel made from plants, must bear a lot of the blame. Since George Bush announced a rush to corn-based ethanol it's done well for American corn farmers - 20 per cent of whose harvest, subsidised by the government, went into fuel tanks rather than flour mills this year. Bush's taste for corn-based ethanol is based partly on trying to break the US's reliance on Middle East oil suppliers, and partly on a (largely misplaced) faith in its ecological credentials. (Its increasingly voluble critics claim that growing grain and then transforming it into ethanol requires more energy from fossil fuels than ethanol generates.)

And, as a result of the vast tracts of farmland now being given over to corn for ethanol production, the price has risen sharply. Hence the tortilla riots in Mexico, last summer, over the price rise in the corn flour that makes the pancakes. Some claim that there is now a war between the 850 million chronically hungry of the world and the 800 million motorists - all fighting for the same food crop. It's a pretty unbalanced battle: the maize to fill a tank for a 'Chelsea tractor' would feed a family of four for three months. In October the United Nations' spokesman on famine, Jean Ziegler, called the biofuel boom 'a crime against humanity'. And as the Economist magazine recently noted: 'The 30 million tonnes of extra corn going to ethanol this year amounts to half the fall in the world's overall grain stocks.'

Last week, after a mass protest at the price of soya beans in Indonesia (which rose because of the shortage of corn and other crops to supply the biofuel industry), Ashok Gulati, director at the International Food Policy Research Institute said: 'It's finally a trade-off between filling stomachs and filling diesel tanks in cars and trucks.'

Some believe this cost increase could be good for the environment. The theory is if you have to pay more for food, you'll be more cognizant of how much you're buying - and wasting. Others aren't so quick to agree and feel that setting prices to encourage certain behavior is risky, especially since the additional money will never be seen by farmers or developing countries.

And while food stamps may not be in our immediate future, experts seem to agree that climate change, water shortages and a rise in energy prices (to name a few) will no doubt impact the cost - and availability - of certain staples currently taken for granted.

Hit the jump to read Alen Renton's entire article about the end of cheap food.

» The Observer