Maltesers, billed as the “lighter way to enjoy chocolate”, have become another treat to shrink in size.

In another chocolate tragedy it appears that Mars, which owns the Maltesers brand, reduced its pouch weight by 15 per cent.

Steve Dresser, a food retail expert, tweeted a picture of a pack of Maltesers advertised as containing 103g of chocolates. However, the out-of-date signage next to the display shows the bag of treats used to contain 121g of chocolates.

Mars said rising costs mean it had to make the unenviable decision between increasing its prices or reducing the weight of its Malteser packs.

“Like all chocolate manufacturers, we have seen the cost of raw materials rise and, while we try to absorb these pressures as much as possible, sometimes we have to make the difficult decision to reduce the size of some of our products so our consumers can continue to enjoy an affordable treat,” the company said in a statement.

“Our focus is always on offering consumers our great tasting, high-quality chocolate brands at the best value for money.”

Galaxy Counters have also been reduced in size and are now being sold in 112g bags – 12 per cent less than the former 126g packets, according to Dresser.

The confectionery industry has a history of “shrinkflation”, where prices remain the same as portion sizes get smaller, but conditions this year have put particular pressure on chocolatiers.

A helpful “milk chocolate index” from analysts at Mintec this week showed the combined price of key ingredients – cocoa butter, cocoa powder, whey, sugar and whole milk powder – is up almost 30 per cent this year.

Cocoa butter has fared particularly poorly, as bad weather in producer countries has combined with a rise in global demand for a chocolate fix, causing prices to jump almost 40 per cent in 2016, adding to steady increases over the past four years.