Writing in The Observer, Monroe, a previous food bank user, says a whole section of society is being cut adrift by the rising cost of supermarket shopping.

The consumer price index (CPI) measure for inflation rose to 5.4% in December, the highest level for nearly 30 years. But Monroe says this figure ‘grossly underestimates’ the true cost-of-living crisis.

The CPI ‘basket’ of goods changes slightly each year and currently includes items such as a leg of lamb, bedroom furniture, a television and champagne. But many of these items won’t be relevant to the poorest members of society who typically buy food from supermarkets’ budget ranges or rely on foodbanks.

According to the Trussell Trust, in the six months of November 2021, more than 5,100 food parcels were handed out every day in the UK.

Monroe says the Smart Price, Basics and Value range products offered as lower-cost alternatives are being removed from supermarkets, leaving shoppers with no choice but to buy supermarkets’ own branded goods – usually in smaller quantities at larger prices.

Monroe has been monitoring these prices for the past decade via writing recipes on her online blog and documenting the prices of ingredients in forensic detail.

She notes that in 2012, 10 stock cubes from Sainsbury’s Basics range were 10p – but cost 39p now or £1 for vegetarian stock cubes. Last year the Smart Price pasta in her local Asda was 29p for 500g. Today, the cheapest bag is 70p; a 141% price rise for the same product.

Monroe shot to fame sharing cheap recipes she created as a single parent, and has used her platform to raise awareness of poverty and hunger.

Her observations come just days after Iceland’s managing director Richard Walker said the budget grocer was losing customers to food banks.

Monroe says she has teamed up with economists, charitable partners, retail price analysts, poverty campaigners and ex-Office for National Statistics staff to compile a new price index that will document the disappearance of the budget lines in supermarkets and the increase in prices of the most basic food items.