Inflation, measured by the Consumer Prices Index, jumped to 2.7 per cent last month from 2.2 per cent in September, largely because of rising food costs. But in the case of chocolate bars it was a case of less meaning more.
The Office for National Statistics said shoppers were getting less for their money because several confectionery products had been reduced in size. This is treated as a price rise by statisticians.
Cadbury recently decreased the weight of Dairy Milk bars from 49g to 45g while still charging 59p.
The Retail Prices Index (RPI) measure of inflation, which includes housing costs, rose to 3.2 per cent from 2.6 per cent.