A four-year-old boy recovering from heart surgery on a controversial hospital ward received a poor level of care, a senior nurse admitted at an inquest today.

William Booth said there were "deficiencies" in the care that Sean Turner received while a patient on Ward 32 at Bristol Children's Hospital.

The little boy died in March 2012 from a brain haemorrhage after previously suffering a cardiac arrest - six weeks after he underwent vital corrective heart surgery.

His parents, Steve, 47, and Yolanda Turner, 45, have given harrowing accounts to the inquest of how they begged doctors and nurses on the ward to help their desperately ill son.

Mr and Mrs Turner, from Warminster, Wiltshire have accused doctors of transferring their son to Ward 32 from intensive care too soon and said they missed the signs of his worsening condition.

They claim their son's death was not isolated and other children with heart problems have died at the hospital.

Up to 10 families are believed to be taking legal action against the University Hospitals Bristol NHS Foundation Trust over treatment on Ward 32.

Mr Booth, who is the matron and lead nurse for paediatric critical care services at the hospital, told Avon Coroner's Court: "I can accept there were deficiencies in care and that the (staffing) ratios could have been better.

"We would never move a child from intensive care to a ward if we thought it was unsafe for them to be there."

Mr Booth outlined the changes that had been made on Ward 32, such as improving staffing levels, training, communication with parents and the setting up of a high dependency unit within the ward - but insisted this was not as a result of Sean's death.

He said that within the newly created five-bed high dependency unit there was a ratio of patients to nurses of 2:1 and throughout the remainder of the ward it was now 3:1.

"The changes have not been made as a direct result of Sean Turner but of course there are lessons learnt and we have addressed those in relation to how Ward 32 operates," Mr Booth said.

He said the trust had also commissioned its own independent review of paediatric nursing across the whole hospital and its findings had been implemented.

The inquest has heard that following Sean's death and that of seven-year-old heart patient Luke Jenkins, from Cardiff, who died nearly a month later, their parents made a complaint to the independent healthcare watchdog, the Care Quality Commission.

The CQC carried out an unannounced inspection and issued a formal warning to the hospital about standards on Ward 32.

Adam Korn, representing Mr and Mrs Turner, suggested there was a direct correlation between the deaths of the two boys, the CQC report and recommendations and the changes on Ward 32.

Mr Booth said he did not accept this and added: "The trust had already undertaken a risk assessment and identified there were issues with high dependency and staff levels, which is why the trust commissioned the independent review.

"I would not agree it was as a result of these deaths."

Mr Korn then asked: "The question screaming out, the question that Mr and Mrs Turner want answering is why these changes were not introduced before he died? Why did it take his death and the CQC report to bring about changes?"

Mr Booth replied: "That's very difficult to answer. I didn't professionally manage the service then..."

When pushed on the point, Mr Booth said that Sean's death was "one factor" in the changes made on Ward 32.

"I believe the care children received on Ward 32 was safe and children received good care and we received many compliments from parents," he said.

"We acknowledge that we can always improve."

Mrs Turner remained outside the court room during Mr Booth's evidence as she did not wish to hear it but returned for the next witness.

Before Mr Booth left the stand, he told Mr Turner: "We are very sorry for your loss on behalf of the nursing team.

"We work very hard and we strive to achieve those high levels of care and maintain them. We are truly very sorry for your loss."

Dr Sara-Louise Hulme, a consultant in paediatric intensive care, told the inquest how she had cared for Sean while he was a patient on the intensive care unit.

Sean was transferred from intensive care back to Ward 32 on February 9, which his parents have described as "the beginning of the end" for their son.

Dr Hulme said that when Sean was moved to the ward he "remained stable" with declining chest drain losses.

On February 16, Dr Hulme said that Sean was deteriorating having been vomiting, suffering from a swollen leg and had an increased heart rate.

She said doctors and nurses on Ward 32 were concerned that Sean may have been suffering from an infection from the femoral line inserted in his groin and the decision was taken to remove it.

"Ten to 15 minutes after removing the femoral line Sean Turner suffered a cardiac arrest," she told the inquest.

"Certainly in the days leading up to February 16 the chest drain losses were reducing.

"That would have been in keeping with Sean Turner progressing in a way we would have expected a Fontan procedure to progress, so I would have expected him to remain on the ward because he was progressing."

Dr Hulme said did not examine Sean on the day of his cardiac arrest but added: "From my understanding there was a recognition that something had changed and there had been an escalation to see whether it would be more appropriate for him to be in the intensive care environment.

"It was very obvious after the arrest that he should come to the intensive care unit."