A second baby who was part of the investigation into blood poisoning from a nutritional drip has died - but officials said the death "does not appear to be related" to the infection.

Public Health England (PHE and the Medicines and Healthcare products Regulatory Agency (MHRA) are investigating cases involving 22 babies who have or might have got blood poisoning in neonatal intensive care units in England.

This includes three babies at the Royal Sussex County Hospital in Brighton.

In a statement, the PHE said: "Another baby has sadly died but this does not appear to be related to the bacillus cereus infection. One other death has previously been reported under this investigation."

Details of the hospital the baby was in when the death occurred cannot be released for confidentiality reasons, a PHE spokeswoman said, but it is known that cases have been recorded at ten hospitals across England.

The first baby, Yousef Al-Kharboush, died on June 1 after contracting a bacterial infection at the neonatal intensive care unit at St Thomas' Hospital in London.

The children were given a batch of a fluid called parenteral nutrition, which is supposed to deliver a variety of nutrients intravenously when a baby is unable to eat on its own.

Professor Mike Catchpole, PHE incident director, said investigations suggest liquids in the drips were contaminated in one day, and confirmed those liquid products are no longer in circulation.

"Investigations to date have suggested the source of the Bacillus cereus infection that has affected outbreak cases was the contamination of intravenous liquid products during a single day of production, which are no longer in circulation," he said.

"PHE is continuing to work with the MHRA on this investigation and to ensure all possible lessons from this serious incident are identified."

The PHE said there have been no new infections since June 2.

Currently there are 18 confirmed cases of infection, and a further four possible cases.

The supplier of the fluid, London-based pharmaceutical firm ITH Pharma, said last week the suspected contamination had been traced to a ''sourced'' single raw material ingredient.