The failings of a doctor responsible for Martha Mills’ care, who died from sepsis, amounted to “gross negligence” and were “particularly grave”, a medical tribunal says.

Her death gave rise to Martha’s Rule in hundreds of hospitals in England, giving parents the right to an urgent second opinion.

The tribunal found consultant Prof Richard Thompson failed to appreciate how seriously ill 13-year-old Martha had become in the summer of 2021, following a bike accident.

On the crucial afternoon, he did not examine her in person or send her to intensive care.

The tribunal concluded Prof Thompson’s fitness to practise is impaired, but whether he will be sanctioned is still to be decided.

Martha was transferred to King’s College Hospital in London in 2021, one of three specialist treatment centres in the UK, after a holiday bike accident left her with serious injuries to her pancreas.

Her parents, Merope Mills and Paul Laity, wrote about their pain and anger over their daughter’s treatment following her death.

During a family holiday, Martha had skidded on some sand and fell heavily on to the handlebars.

“It was a difficult, tricky injury, but it did not have to be a fatal one,” Merope has said.

But she stayed in the hospital for the next month.

She developed an infection and then signs of sepsis – when the body’s response to an infection is overwhelming and ends up injuring its own tissues and organs – but this was not managed properly.

An inquest found that she could have survived her injuries if she’d been referred to the specialist children’s intensive care in the hospital promptly, and received better care.

Interviewed on BBC Radio 4’s Today programme in 2023, Merope Mills said her family were not listened to by senior doctors on several occasions and were “not given the full picture” about Martha’s deteriorating condition.

Over the past few weeks, the Medical Practitioners Tribunal Service has heard allegations from the doctors’ regulator, the General Medical Council (GMC), that Prof Thompson failed on several counts over his care of Martha.

He was the consultant on call on her ward on 29 August 2021 – two days before she died.

The tribunal said it was “evident” that by around 17:00 that day Martha had “several high risk indicators” including her heart rate, blood pressure, breathing and a rising temperature, which “indicated a sudden and significant deterioration”.

It said Martha’s condition, which included a new rash, justified her being moved to intensive care but “this opportunity was not taken”.

Later that evening, Prof Thompson was called at home by a colleague about Martha’s continued fever. He had already seen her on his morning ward round, but did not return to the hospital to examine her in person.

Prof Thompson has said one of the reasons he wanted to keep Martha on his ward was not to distress her parents, but the tribunal said this did not justify withholding or delaying her move to intensive care.

The Medical Practitioners Tribunal Service has now decided that Prof Richard Thompson’s fitness to practise had been impaired.

The tribunal said this would reassure the public and send a message to doctors about the importance of following the fundamental principles of good care.

Martha’s parents raised concerns about their daughter’s care to the regulator, the General Medical Council, in 2022.

Responding to the tribunal’s findings Martha’s parents said: “It is important to us that allegations denied have been found proved and the gravity of mistakes that led to our daughter’s preventable death has been recognised.

“We will always have in our minds the failures of culture, training and policy on Rays of Sunshine Ward at King’s College Hospital, as well as the responsibility of individuals.

“We’d like to thank all the thoughtful doctors who have helped us to understand what happened to Martha.”

The hospital that looked after Martha has admitted mistakes were made, and the trust said previously in a statement that it “remains deeply sorry that we failed Martha when she needed us most”.