So what's going on? And can this be fair?
ShrinkingThe change came as all the classic size bars were redesigned in August. The pieces are curved, which has enabled the company to shave a chunk of chocolate from each. They didn't make any announcements about the change in size, and presumably hoped it had slipped under the radar. However, this week the BBC's Watchdog programme discussed the issue, after viewers contacted them to complain.
So is this purely a result of Cadbury's being taken over by the US giant Kraft in January 2010? It's not the only chocolate shrinkage that has been going on at the company. Last year it shrunk the 140g bars and the size of a tin of Roses.
KraftyKraft got people's backs up when it bought a traditionally British company, with its roots so firmly in the midlands that it founded a village - Bourneville. It didn't help that soon after buying the company it went back on a promise not to close one of the UK factories (after discovering just how advanced the plans for relocation were).
However, does this necessarily mean it's a company with an evil intent to deprive us of chocolate?
When questioned about the change, Cadbury's said that it was responding to increases in manufacturing prices. The price of sugar has gone through the roof, and the rising price of fuel means that running production and then transporting chocolate around the world costs a small fortune. A spokesperson told the programme: "Making these small reductions [in size] allows us to hold prices at current levels."
And it's not the only company to have done so. A year after 11 chocolates disappeared from a standard tin of Roses, the size of a tin of Quality Street shrunk too - as Nestle made exactly the same call. The Swiss competitor also took one triangle from its Toblerones, so that it could still be priced at £1. And over the past couple of years we have seen the size of Maltesers, Mars, Snickers, Yorkie and Rolo all shrink - removing the last Rolo from the packet.
Chocolate isn't the only area where products have been getting gradually smaller. According to research by Which? Dairylea, Pampers and Pringles have all been gradually reducing the size of packets in order to cut costs.
Which? executive director, Richard Lloyd, said at the time of the research that people: "shouldn't be expected to carry a calculator around the supermarket in order to work out the best value. We want supermarkets to help their customers through clear and consistent unit pricing."
But what do you think? Is this a sensible response to rising prices, or should the company have been more up-front about the change?