A drug that can help prevent premature babies from developing cerebral palsy will be offered across the NHS.

The drug which will be recommended to thousands of expectant mothers, could prevent around 300 babies developing the condition per year.

For babies born at less than 28 weeks, the risk of developing cerebral palsy is one in 10, for those born at full term the risk decreases to 1 in 1000.

Magnesium sulphate, which costs just £1 per dose, can reduce the chance of babies developing the condition by around 30 per cent, when given to women who are about to go into premature labour if they are under 30 weeks, NHS England said.

The drug acts as a “helmet” around the baby's brain and stablises their cells to be stronger against the adverse effects of premature birth.

“You give it to the mother and the medicine crosses the placenta into the baby and gets to the babies brain, within the brain it seems to stablise cells,” Dr Pat O’Brien, a consultant obstetrician and spokesman for the Royal College of Obstetricians and Gynaecologists (RCOG), said.

“The wall of the cell seems to be a bit more stable and strong, which means it’s more able to withstand the trials and tribulations of being born prematurely.