The health watchdog has raised "serious concerns" about the care of children at a hospital in Essex following the death of a 10-year-old girl.
The Care Quality Commission (CQC) performed an unannounced inspection at Basildon and Thurrock University Hospitals NHS Foundation Trust after "a number of serious incidents involving the care of children at the trust".
A spokeswoman confirmed the inspection on November 3 was prompted by the death of the girl and a medication overdose of a baby.
It is understood that the girl was treated at the trust before she was transferred to St Mary's Hospital in west London where she later died. The baby is expected to make a full recovery.
The CQC said that "rapid and sustainable improvement" is needed at the trust. The watchdog has also ordered an independent investigation into the paediatric services.
Andrea Gordon, CQC deputy director of operations (regions), said: "What our inspectors found at the trust on November 3 was completely unacceptable.
"We have taken this action to assist in driving through improvements which have a positive impact on the people being cared for at the hospital. It is imperative that the trust now ensures it makes changes which are sustainable, embedded and maintained for the future."
Clare Panniker, Chief Executive of Basildon and Thurrock University Hospitals NHS Foundation Trust, said: “I want to assure the local community that we are absolutely committed to improving the standards of care which we deliver to children.
“By commissioning a review of our paediatric services we can be sure we are looking at every area to best meet their needs.”