A leading expert in medical ethics has called for new mediation panels to prevent the “entrenched disagreements” that surrounded the treatment of Alfie Evans, the 23-month-old boy who died yesterday, almost a week after his life support was withdrawn.

Dominic Wilkinson, professor of medical ethics at the University of Oxford and a neonatal consultant, said that independent mediators could help people such as Alfie’s parents, Thomas Evans and Kate James, who repeatedly clashed with doctors over their child’s treatment for a degenerative brain disease, culminating in a protracted high court battle.

The call for a fresh approach came amid an outpouring of grief from well-wishers, including Pope Francis, with more than 1,000 people gathering near Alder Hey children’s hospital in Liverpool to mourn Alfie’s death early yesterday morning.

Wilkinson, a consultant neonatologist at Oxford’s John Radcliffe Hospital and specialist in newborn intensive care and medical ethics, said that there needed to be “greater ethics support” within specialist children’s hospitals to help all parties reach a consensus in future cases.

“Looking forward, there is a real need to try to resolve disagreements between parents and doctors. Entrenched disagreement can reach a point where it’s very difficult to step back from,” he said.

“I think there are an interesting number of possibilities – in particular, formal mediation involving somebody independent of the hospital and the family who can sit down with both parties and try to help rebuild communication and help find common ground,” he added.

Hours after the news that Alfie had died at 2.30am – five days after his life support was withdrawn on Monday when a last-ditch appeal to the high court was turned down – mourners carrying flowers began arriving at Alder Hey.

By early afternoon, hundreds had congregated in Springfield Park, near the hospital, to release blue and purple balloons exactly 12 hours after the boy had died.

One card left on flowers laid outside the hospital read: “We fell in love with a little boy we never knew. Alfie will be forever engraved in our heart. Fly high little man.”

Among the messages of support was one from the Pope, who took a personal interest in the case and tweeted his condolences, writing: “I am deeply moved by the death of little Alfie. Today I pray especially for his parents, as God the Father receives him in his tender embrace.”

A statement followed from Archbishop of Liverpool Malcolm McMahon,, on behalf of the Catholic Bishops’ Conference of England and Wales, which said: “All who have been touched by the story of this little boy’s heroic struggle for life will feel this loss deeply. We must thank Tom and Kate for their unstinting love of their son, and the staff at Alder Hey Hospital for their professional care of Alfie.”

Alfie Evans’s parents Kate and Tom. Photograph: Philip Toscano/PA

Earlier, Alfie’s father Thomas had written a message on Facebook stating: “My gladiator lay down his shield and gained his wings … absolutely heartbroken.”

His sister, Sarah, told the crowd at Springfield Park: “Our gorgeous little warrior took his last breath at 2.30 this morning. Our hearts are broken. We are absolutely shattered as a family. Thomas just wants to thank you all for the support you’ve all shown. There’s only one Alfie Evans.”

A spokesman for Alder Hey offered Alfie’s family their “heartfelt sympathy and condolences” and said it had been a “devastating journey” for the parents.

“All of us feel deeply for Alfie, Kate, Tom and his whole family and our thoughts are with them.

“This has been a devastating journey for them and we would ask that their privacy and the privacy of staff at Alder Hey is respected.”

It signalled a tragic end to a fractious relationship between Evans and Alder Hey with the father regularly speaking out against hospital bosses as he argued for his son to be transferred to a hospital in Italy with links to the Vatican.

Alfie had been in a semi-vegetative state for more than a year and scans of his brain had shown that almost all of it had been destroyed. Judges had agreed with doctors that further treatment would be futile and that there was no hope of him getting better.

His parents, both in their early 20s and from Liverpool, had insisted their son was not in pain or suffering but lost a string of cases in the high court, court of appeal, supreme court and European court of human rights.

Wilkinson also called for the government to increase support and funding for clinical ethics committees.

“These committees are very poorly resourced within the NHS but they are important both for families and for health professionals in the context of these disagreements. They help clarify what the key issues are and try to find ways forward without having to go to court.

“They are a resource and a way of trying – with the child’s interests right at the front of their minds – to sidestep the particular disagreement where that has occurred between families and professionals,” he added.

He said that such committees existed in about half of NHS trusts but tended to be ad hoc and inadequately supported.

“They need to be better resourced, better funded and more of them,” said Wilkinson.