Cocoa prices have surged in London, fuelled by fears that political unrest in Ivory Coast, the world's biggest producer, could disrupt supplies.
The chocolate industry depends on steady supplies of cocoa
December cocoa futures rose 12% in London trade to £1,019 a tonne, their sharpest rise in more than five years.
Ivory Coast was gripped by rioting at the weekend after France disabled the country's air force in revenge for an attack on French peacekeeping forces.
Analysts said the unstable situation could drive prices higher still.
"Any story of clashes between protestors and the French will result in further reactions in the market," said Jonathan Parkman at Calyon investment bank.
French troops destroyed most of the Ivory Coast's air force on Saturday in retaliation for the death of nine French peacekeepers in a government raid on rebel positions in the north of the country.
The move triggered violent protests against the large French expatriate community in the commercial capital, Abidjan.
Ivory Coast has been divided since a failed coup attempt two years ago.
The north is in the hands of rebels, while the south, where the majority of cocoa is grown, is controlled by the government of President Laurent Gbagbo.
France, Ivory Coast's former colonial ruler, has sent thousands of troops to the country in order to monitor a ceasefire, and to maintain a buffer zone between government and rebel forces.
President Gbagbo has appealed for calm, while a stand-off between demonstrators and French forces was continuing in Abidjan on Monday, according to the latest reports.