The number of nurses looking after sick and premature babies is reaching crisis point in London, say campaigners.
Prematurity carries many health risks
Premature baby charity Bliss says an extra 540 nurses are needed to bring intensive care units up to recommended "safe" levels, of one nurse per baby.
It says many mothers and babies are being moved to units miles from their homes, to find a staffed cot for them.
Bliss will give evidence on Wednesday at a London Assembly inquiry into neonatal intensive care in the city.
The charity, which has been conducting a national survey of 220 neonatal units, based its results on responses from 153.
It found that only 2% of units in the UK had the recommended number of staff.
In London, only Great Ormond Street children's hospital had one nurse for every baby in need of intensive care.
Bliss says lots of premature babies are born in London, as those at risk include teenage mothers and older women having IVF treatment. There are high numbers of these in the city.
Emily Robinson, from Bliss, told BBC London: "In London, lots and lots of premature babies are being born so really we need these extra neonatal nurses to keep up with demand on the service."
The Royal College of Nursing will also give evidence to the inquiry on Wednesday.
It is calling for more neonatal nurses and better provisions for families who are being treated away from home.
Spokeswoman Fiona Smith said that one nurse for one baby was the "gold standard" in neo-natal intensive care, but said in reality there were UK-wide shortages.
"This can be a difficult time for parents who want their babies to receive the best care they can.
"Unfortunately this is not always possible at a local unit or hospital."