Aid organisation Unicef advises food banks not to give out powdered milk formula to financially-strapped families because of “concerns for the safety of the baby”.

Its guidelines state “there is an array of different products on the market and getting the right one from a food bank cannot be guaranteed”, The Sunday Times reports.

But according to British charities, this has resulted in desperate mums watering down what little formula they have or feeding their youngster porridge or cow’s milk which the NHS says is unsuitable for babies under the age of one.

Charities are urging Unicef to change its guidelines adding that some mums are being forced to go without food themselves to make sure their children can be fed.

Dental nurse Lauren Elrick was forced to water down her daughter Robyn’s formula due to financial strains, the Sunday Times newspaper reports.

The 26-year-old from Peterhead, Aberdeenshire, was on maternity pay but that had been stopped and her partner’s working hours were cut leaving her with no choice.

She told the Sunday Times: “It was heartbreaking to be in this position because as a mum I wanted to do everything I possibly could for my daughter, especially to provide her with food.”

In the end the couple borrowed cash from Elrick’s parents to help pay for Robyn’s milk before they found out about AberNecessities, a local baby charity that does not follow the Unicef guidance so was able to provide her with formula.

Danielle Flecher-Horne, founder of AberNecessities, said: “I can assure you, there is no worse sound than hearing a mother crying down the phone, desperate to feed her baby.”

However, charities have said babies across the UK are going hungry because food banks are being told by councils not to give out formula milk.

This ends up costing struggling parents around £10 a tub with some infants needing two tubs a week.

Erin Williams, 40, co-founder of Feed, is asking for the guidelines to be reviewed.