Jack Monroe has praised Asda for cutting the cost of products in its Smartprice range – and making them more widely available.

The poverty campaigner had gone viral last month after writing a Twitter thread to warn official inflation figures “grossly underestimated” the impact that the cost-of-living crisis was having on Britons with low incomes.

Ms Monroe, who once used food banks and has produced affordable recipes, shared evidence that showed the price of the cheapest pasta in her local supermarket had surged by 141% in one year, while rice cost 344% more.

By contrast, she pointed out that upmarket ready meals had remained fixed at £7.50 for a decade.

Asda said it had taken her comments on board – and vowed to stock its lowest-price range in all 581 stores and online.

Three-and-a-half weeks on from her “accidentally viral tweet”, Ms Monroe said she “actually gasped” after heading into her local supermarket to see what, if anything, had changed.

She shared pictures showing that the cheapest pasta available was now 29p per 500g – the same price as a year ago, and a stark contrast to the 70p that was being charged last month.

A 1kg bag of long grain rice, tins of baked beans, canned spaghetti and jars of mild curry sauce had also returned to the prices seen in February 2021.

One of Ms Monroe’s biggest concerns centred on the disappearance of many Smartprice products from shelves – which meant only more expensive alternatives remained, affecting “the poorest and most vulnerable people in our society”.

But as she browsed the aisles, she said she was “really struggling to contain my joy” after discovering Smartprice crunchy peanut butter was back in stock – alongside mandarin pieces, peace slices, rice pudding, jam and marmalade.

Sharing pictures of the shelves, Ms Monroe wrote: “There were many other joyous moments in my (normally quite mundane and functional) shop. Honestly, it was like bumping into old friends. Hey you guys, I’ve not seen you around in AGES. Welcome home!”

Praising Asda, she added: “The turnaround for this has been almost immediate – the speed at which they responded, not just with words, but with exactly what they said they would do – has been absolutely remarkable.

“The impact that this will have on millions of people is impossible to overstate. And of all the supermarkets that reached out to me in the last weeks, Asda have been the only ones to actually act on our conversations and make things right.”

Overall, Ms Monroe said it was her “happiest shopping experience in over a decade” because she could put extra treats in her shopping basket – a stark contrast to the past, when price rises meant she had to put things back.

The campaigner is currently creating on a new price index that is designed to monitor the “insidiously creeping prices” of basic food products, and Ms Monroe’s work has also prompted the Office for National Statistics to change the way it releases inflation data.

ONS data shows that inflation hit 5.4% in December – its highest level in almost 30 years – and figures for January will be released on Wednesday.

Energy prices are also surging, and the Bank of England is expecting that inflation will hit 7.25% in April, with its economists warning that the squeeze on household budgets will create the biggest slide of living standards on record.