Consumers are suffering "sneaky" price rises on some everyday grocery items as big brands quietly reduce the size of products, a watchdog has warned.
Which? said it continued to find evidence that commonly-bought items such as tea, cheese and washing powder had shrunk - and in some cases actually increased in price.
It found that Sainsbury's increased the cost of Tetley Blend of Both tea from £2.55 to £2.75, despite the pack shrinking from 80 tea bags to 75.
Asda increased its price for Philadelphia Light Soft Cheese from £1.84 to £1.87 after the pack shrank 10% from 200g to 180g.
Surf Essential Oils Powder Tropical Lily & Ylang Ylang remained priced at £5 in Ocado and Tesco despite shrinking from 25 washes (2kg) to 23 washes (1.61kg). And at Asda, Morrisons and Sainsbury's, the prices of Birds Eye Select Mixed Vegetables and Hovis Best of Both bread remained the same despite shrinking.
The watchdog reported that the majority of manufacturers said it was retailers who ultimately set the prices of products. But it pointed out that supermarkets were unlikely to drop prices unless the wholesale cost fell.
It said: "Products are losing 50g here and a few centimetres there, which is all adding up to a more expensive shop without you knowing why."