A hospital in south-west London is calling on new mothers to help replenish its near-empty milk bank.
The neo-natal unit at Kingston Hospital is close to full capacity but has a shortage of milk.
The donated milk is used to help the mothers of premature and sick babies who often have not had time to produce enough milk to feed their own children.
New mothers that do not smoke, are drug-free and drink less than two units of alcohol a week are urged to donate.
Breast milk, which contains essential nutrients, antibodies and calories, is the only option for premature babies who cannot digest formula.
The hospital asks for mothers of babies of six months and under to donate at least one litre of milk, which is then tested and pasteurised ready to be given to any baby in need.
Joanne Ferris, whose son Patrick was born 13 weeks premature, was one of several mothers on the unit to benefit from such donations.
She said: "I'll be eternally grateful to women, I don't know who they are, whose breast milk kept him alive for the first two weeks of his life.
"When they're that premature their tummies can't take formula. They have to have breast milk and because I was poorly after giving birth, I didn't meet him for three days."
Jill Hodkingson, a matron on the ward, said: 'We've recently had quite a big demand, we've had lots of small babies, maybe more than we would normally, and this is what happens in neo-natal units.
"There's no particular reason for it, we just go through different phases where we have more small babies and sometimes the milk becomes contaminated with certain bugs we can't allow to be passed on to the babies."
The hospital has urged suitable donors to log on to borntoosoon.org.uk for more information.