In an interview with Sky News, WHO called out the "profit-driven" multinational manufacturers for "manipulating the price" of their baby formulas.

The most recent research shows prices in the UK have risen 24% over the past two years, while the cheapest brand has jumped by 45% in that time.

WHO has urged governments to intervene on behalf of struggling families and find a way of reducing the prices in the shops.

In May, Sky News uncovered the desperate measures many parents are taking to feed their babies including stealing formula, buying on the black market, watering down bottles or substituting formula for condensed milk.

WHO technical officer, Laurence Grummer-Strawn, told Sky News: "It is shocking to be seeing a high income country like the UK facing these kinds of problems where mothers can't afford to feed their babies."

When asked if it amounted to exploitation, Mr Grummer-Strawn said: "Yes, I think we can say that when you see that these prices are being driven down to the consumers and having to pay extremely high prices.

"They're in a very vulnerable situation, that they have infants that have to be fed and there aren't many alternatives out there for them and there aren't really other companies they can turn to.

"You're exploiting them to increase the profits of these companies, and they have huge profit margins."

Speaking about solutions, Mr Grummer-Strawn explained: "We really need government action to address either on the price end or in ways to help those families directly."

"Lowering the prices can help these families, but it needs to be in a sustainable way," he added.

"We have to have government action. To be setting up a situation where people are dependent on these baby banks and food banks to be providing this, that's not a sustainable way for families to get what they need."

Baby banks and food banks across the UK have reported a surge in families in need of help - often parents who are in work but are still struggling to afford formula milk and other essentials.

Last month Sky News reported on the rationing that many baby banks said they are now having to introduce because they don't have enough donated formula to distribute to all those who need it.

Many of the charities have said they are worried the workload is unsustainable.

Mr Grummer-Strawn added: "I think that what we're seeing here is largely companies taking advantage of opportunities that other things are getting more expensive, so let's make ours more expensive as well.

"Our concern is that they're out to maximise their profits.

"And from a business perspective, and their shareholders, maybe that's what their shareholders want. They want the highest profit.

"We're certainly trying to find ways to reach out to investors and say, 'you know, where's the ethics in this?', and try to get investors to think about investing in an ethical way and therefore either don't invest it in these companies, or choose the companies that are making the most ethical decisions and tell them about the harms of the way that these products are being marketed, the way the prices are being manipulated."

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Mr Grummer-Strawn added: "At the heart of this are families simply trying to keep their babies fed when, for whatever reason, their child relies on bottle feeding.

"We really want to make sure we're not making mothers feel guilty. This is not their fault."

The problem is, he added, "that the government hasn't stepped up and supported them in ways that they need to".

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While most of the main manufacturers did not respond directly when Sky News put WHO's comments to them, they have all told us higher production costs are the reason for the price rises.

Danone, which makes the Aptamil and Cow & Gate brands, did respond to say it is facing "unprecedented increases in the cost of ingredients, manufacturing, storage and transport".

A spokesperson said: "Where possible we have always tried to absorb as many of these cost increases as possible."

Danone added that it does try to help parents but added: "Ultimately, individual retailers set the selling price in their stores for all products."

Westminster officials have consistently told Sky News that the government is helping with the cost of living but did not respond to WHO's concerns.