When recession hit London just over two years ago, Clive Schlee, the chief executive of the popular sandwich bar chain Pret a Manger, reacted by cutting the price of his stores' filter coffee to 99p (Dh5.83) a cup. It was enough to bring back many Pret customers who had resorted to making their own sandwiches from home.
Since then, coffee prices have soared, and wheat, milk, meat and egg prices have followed. According to the UN, food prices are at a 21-year-high and are set to rise further. But Pret is sticking to its 99p coffee.
"Food prices are a problem, of that there is no doubt. But we can't just demand that our suppliers cut their prices. We can't and won't blackmail them," Mr Schlee says. So far, so ethical.
But the rising cost of food is putting many food manufacturing businesses and restaurants, as well as households, under pressure in the developed world. In the developing world, the impact of high food prices can be fatal.
Data from the Organisation for Economic Co-operation and Development put UK food inflation at 6.3 per cent, well ahead of the average of 2.1 per cent for the Group of 7 nations. Karen Ward, a senior global economist at HSBC, believes such increases cannot be borne for long.
"Even in the developed world, I think we have very, very low wage growth, so people aren't getting more in their pay packet to compensate them for food and energy [rises], and I think we could see social unrest, certainly in parts of the developed world and the UK as well."
Soaring food prices have played a part in the sudden uprisings in Egypt, Tunisia and Libya. According to the Associated Press, about 40 per cent of Egyptians struggle along at the World Bank-set poverty level of less than US$2 (Dh7.34) per day. Analysts estimate food price inflation in Egypt is currently at an unsustainable annual 17 per cent.
Back in the UK, food costs have gone up for eight months in a row, with the National Farmers Union forecasting the trend will continue for the rest of this year.
Wheat has almost doubled in price over the past six months, and rising demand has caused the cost of sugar to rise by 14 per cent over the past 12 months. Arabica coffee has increased by 125 per cent in a year.
Several factors are contributing to the rising price of foodstuffs across the world. There is a link between high food prices and the escalating cost of crude oil - especially in a country such as UK, which now imports much of its food.
Increasingly, though, some foodstuffs are actually substitutes for energy itself. If crops can be used to replace fuel, a link between energy prices and food prices is created.
Every year there is increasing demand for foodbecause of population growth and from economies such as China, where people are emulating the West by consuming more meat and milk products.
Extreme weather that has destroyed crops has also been partly to blame for the rising cost of basic foodstuffs.
The finger has also been pointed at the role of speculators, investors who have played the food commodity markets as they might the financial markets.
Paul Polman, the chief executive of the global food giant Unilever, has warned the situation is untenable. "One of the main things in food inflation is that it has attracted speculators for short-term profits at the expense of people living a dignified life," he said.
There is now more money being bet on the price of cocoa than the value of all the cocoa available. About 80 per cent of the trading in certain foods is now speculative rather than functional.
London's hedge funds have been accused in some quarters of being among the worst offenders in speculation. Anthony Ward, a hedge fund manager who owns 7 per cent of the world's cocoa supplies - or about 5 billion chocolate bars - is one who has achieved a degree of notoriety and a nickname - Choc Finger.
But the pressure to tighten regulation around commodities trading is growing. At the end of this month, the European Commission is due to release a report on commodities speculation. Publication of the original study was postponed when France lampooned its findings: that speculation had played no part in rising food prices.
The French are clear that speculators are compounding long-term price rises by creating short-term spikes and want regulations imposed quickly. US regulators are also taking action.
In London, the move will be resisted strongly by the financial community. But the government does not appear to be keen to take on this fight. Yet, as the public begins to link city traders' behaviour to the cost of its weekly grocery shopping, the chances are that public opinion will call for the British government to back tougher rules, too.