One baby died and 18 others became ill in when they were poisoned by suspected contamination in their drip feed / Corbis

Parents had to face questioning by police after newborn became ill

The mother of a newborn baby who had a heart attack that may have been caused by a bad batch of food given to the child in hospital is threatening legal action against the manufacturer.

Frances Blacklock said she and her partner were questioned by the police after their son Mason became ill amid concerns he had been poisoned.

However the year-long investigation by the Medicines and Healthcare Products Regulatory Agency (MHRA), the hospital and the Metropolitan Police concluded that the illness was caused by excessive magnesium in an intravenous feed given to the baby, according to her law firm.

The case came to light after one baby died and 18 others became ill last month when they were poisoned by suspected contamination of another privately manufactured drip feed, which was sent to 22 hospitals in England.

Mason was born by Caesarean section in February 2012 and needed surgery to reposition his bowel and correct a birth defect. It appeared to be a success, but his condition suddenly worsened at University College London Hospital.

Ms Blacklock has now instructed lawyers to obtain redress from the manufacturer of the feed.

“The investigation was awful, even my partner and I had to be eliminated from suspicion. To be involved in something like that was just heartbreaking, especially when all we cared about was Mason getting better,” she said.