Britain's cheapest brands of pasta and bread have surged in price over the past year, but overall the cost of lower-priced food and drink staples has risen at a similar pace to average prices, the Office for National Statistics said.
Anti-poverty campaigners have pointed to sharp price rises in the cheapest categories of many food staples, and surveys have shown growing numbers of Britons skipping meals as they are squeezed by the highest consumer price inflation in 40 years.
Last week Britain's government announced 15 billion pounds of grants to households to pay soaring energy bills, on top of 22 billion pounds of support earlier this year.
The cost of the cheapest 500 gram (17.6 oz) pack of pasta at a British supermarket last month was 53 pence ($0.67), a 50% increase from 36 pence a year earlier, while the price of an 800 gram loaf of bread rose by 16% to 54 pence.
In cash terms, the biggest increase was in the cost of 500 grams of minced beef, which rose by 32 pence to 2.34 pounds, a 16% increase.
However, average prices for the cheapest brands of food and drink across 30 staple categories rose by 6-7%, the ONS said, the same as for food and drink overall.
"There is considerable variation across the 30 items, with the prices for six items falling over the year, but the prices of five items rising by 15% or more," the ONS said.
The cost of potatoes fell 14%, cheese prices were down 7% and pizzas cost 4% less than a year before.
The ONS described its analysis as "highly experimental" and said the results were sensitive to the exact goods chosen in particular categories.
Bank of England Governor Andrew Bailey warned this month that Russia's invasion of Ukraine could have "apocalyptic" further consequences for food prices, especially for developing counties. Read full story
Both Russia and Ukraine are major exporters of grain, vegetable oil and other foodstuffs.
($1 = 0.7914 pounds)
Cost of pasta and bread surges for Britain's poorest
Anti-poverty campaigners have pointed to sharp price rises in the cheapest categories of many food staples