Supermarket own brands are not only cheaper than A-brands, but are also likely to include more product, according to research by consumers’ union Consumentenbond, based on random samples.

“A-brand packaging is often the same size as own brands so it looks as if the contents are the same,” said Consumentenbond director Sandra Molenaar. “But that does not need to be the case. And sometimes A-brand packaging is bigger but full of air. This is particularly the case with washing powder and dishwasher tablets.”

For example, a standard box of Sun dishwasher tablets contains 21 blocks, but supermarket own brands have 40 tablets in a smaller box.

Among other examples found by the consumer group were a box of Tempo tissues containing 70 tissues whereas many own brand boxes have 100 – some 43% more. And a roll of Dumil aluminium foil is 10 metres long which compares very badly to one particular own brand which had 30 metres.