Cost of living crisis will be 'fatal' for some children, says food campaigner Jack Monroe

• Watch Jack Monroe giving evidence to MPs at the Work and Pensions Committee.

Food writer and campaigner Jack Monroe has told MPs that the impact of the cost of living crisis on the "millions of children living in poverty in Britain" is "going to be, in some cases, fatal".

She added: "And that's not a term that I use lightly."

The high profile anti-poverty campaigner, from Southend, told the Work and Pensions Committee that the home situation of children living in poverty was "already untenable" and had been increasingly so over the last decade.

Ms Monroe has argued that the increasing price of everyday essentials and decreased availability of value product lines had left poorer individuals seeing a higher rise in the cost of living than had been reported in existing inflation measures.

Following the tweets on the cost of living, it was announced that statistics officials had pledged to revise the way they calculate inflation.

They agreed to use her chosen name for the measure.

The Vimes Boots Price Index is named after author Sir Terry Pratchett's Vimes Boots Theory Of Economics.

It is named in honour of Pratchett's Discworld character, Sam Vimes, whose musing on how poverty affects the ability to save in the longterm buy a long-lasting pair of boots, forms his theory of economic unfairness.

Ms Monroe's tribute was welcomed by his estate at the time, who permitted the name be used as well as by his family, who said the late writer would have been proud to have seen his work used in that way.

In Westminster on Wednesday, Ms Monroe gave evidence on her concerns about the rising cost of living to the committee, telling MPs: "A £20 a week food shop a few years ago gets probably about two thirds of what you'd be able to get for that £20 now.

"And that's not people deciding not to go to the theatre or not have legs of lamb or bottles of Champagne, that's people deciding 'we won't eat on Tuesday or Thursday this week' or 'we'll turn the heating off' or 'we'll skip meals'."

Ms Monroe, who welcomed Asda making good on its pledge to roll out its lowest-priced value range to more stores, added: "The onus on ensuring that people are able to feed themselves adequately and decently and nutritiously shouldn't fall on the price point of pasta in a supermarket.

"It should be something that people don't have to do - those macro calculations walking round the supermarket. It should be something that's available to everyone regardless of their circumstances."

When asked why figures appeared to suggest that the affordability of food had improved in recent years, Ms Monroe said: "It's not that the affordability of food has got better, it's that the expense of everything else has got worse.

"Food is one of the most fundamental human necessities for survival. It's the last thing that any household chooses to cut in their budget.

"But rent has gone up, gas has gone up, electricity has gone up, council tax has gone up, the general cost of living has gone up to a point where people have less to spend on food in their household expenditure.

"In my experience of 10 years on the coalface of anti-poverty work, I can tell you that people are just eating less or skipping meals or having less nutritious food, bulking out on that 45p white rice and 29p pasta in lieu of being able to have fresh fruit and vegetables and nutritionally balanced meals.

"It's not that food has got cheaper because it certainly hasn't. It's that everything else has got more expensive so there's less in the household budget for food."