Grieving parents Steve and Yolanda Turner are calling for a public inquiry and considering legal action over the death of their four-year-old son Sean in hospital.

Last week an inquest ruled that there were lost opportunities in his care for staff on Ward 32 at Bristol Royal Hospital for Children.

Sean died in March 2012 from a brain haemorrhage after previously suffering a cardiac arrest – six weeks after he underwent vital corrective heart surgery at the hospital.

At the end of the eight-day inquest last Thursday Avon Coroner Maria Voisin recorded a narrative verdict, despite finding that more could have been done for Sean in the post-operative period.

She added that she had been told of changes made by University Hospitals Bristol NHS Foundation Trust since Sean’s death and would not be writing a Prevention of Future Deaths report.

But the Warminster couple believe the Ms Voisin’s verdict did not go far enough and are demanding an independent inquiry into Sean’s death.

Mrs Turner, 45, said: “We still feel the coroner was really weak and we’re actually quite angry about that, because she had an opportunity to prevent future deaths and make a report and she didn’t do that. She should have done that as the threshold is quite low.

“She didn’t mention any of the poor care on the ward, she avoided that, but the lost opportunities that she found occurred as a consequence of poor care on that ward.

“We want to write a complaint to the chief of coroners about this coroner and we also want to put pressure on the Department of Health and ask them what they are going to do about this and get a public inquiry.”

Mr and Mrs Turner claim their son’s death was not isolated and other children with heart problems have died at the hospital, including Luke Jenkins, aged seven, from Cardiff.

The hospital will come under more scrutiny in the coming months as four more inquests are held for children who were treated there, while up to 10 families are taking or considering legal action against the hospital trust.

Mr Turner, 47, added: “I think at the start it was about finding out the truth about what happened to Sean and I think during the inquest we’ve learnt a lot, I think we can piece together in our minds exactly what has happened to Sean.

“Now we have moved on to making sure that place is safe and saving other children, as it’s not safe, it can’t be safe with all these people coming out so recently. It needs that public inquiry to make it safe for others, even if at the end of the day it saves one life, it has to be worth it.”

The inquest heard how doctors transferred Sean from intensive care too soon and staff failed to pick up signs of his worsening condition while he was on Ward 32.

The chief executive of the Trust Robert Woolley offered his “sincere apologies” to Mr and Mrs Turner following the inquest and said changes had been made.

But the Turners say that is not good enough and after hearing the evidence about Sean’s treatment on Ward 32, they want a public apology from Mr Woolley for the failings in Sean’s care.

Mrs Turner said: “Mr Woolley apologised for the stress caused to us, he didn’t apologise for the failings in Sean’s care or for suffering that Sean endured. That wasn’t an apology.

“He was forced to say that because of the coroner’s verdict, he had no choice. Otherwise, why didn’t he apologise two years ago? We met him and he apologised for the experience we had, but he didn’t take responsibility for the failings that caused Sean’s death.

“I’m sorry but Mr Woolley needs to resign. He needs to go from that job. Patients are still at risk at that hospital with Mr Woolley at the top, if he can’t take responsibility for the failing at his hospital.”