And there were points during the 2010s when the number of claims were higher per A&E attendance than they were now before falling.
But the sustained increase over the past five years is causing concern, say experts.
The pattern is not being repeated in other areas, such as maternity or orthopaedics, and the low point in 2020-21 is thought to be unrelated to any behaviour changes by patients during the Covid pandemic as it takes three years on average for a claim to be submitted.
The Royal College of Emergency Medicine told the it was worried about the rise, linking it to increasing pressure and long delays being seen in A&E in recent years.
Over the last two years one in 10 patients who attended A&E spent more than 12 hours waiting to be treated or discharged.
RCEM’s Dr Adrian Boyle said the figures were “sobering”.
“This is a concern. But it is not surprising when you see how busy departments are. People are staying longer and pressure on staffing is increasing.”
But he said clinical negligence cases were still relatively rare – happening in only around one in every 17,000 attendances.
NHS Resolution, which supports NHS trusts with clinical negligence claims, said it was taking action on the “high volume” of claims and has published reports to help the NHS learn from mistakes.
Such mistakes include missing the signs of acute deterioration in patients, failing to order the necessary tests and scans and making incorrect diagnoses.
NHS England said claim numbers were not a good measure of current safety because of the lag between the incident happening and claims being logged, adding there were signs A&E waiting times had started improving.
Matthew Hopkins, of NHS Alliance, which represents hospitals, said health bosses were “making every effort is made to ensure safe, high-quality care, and that lessons are learned when that falls short”.
For Stephen, “every waking hour” is spent worrying about his son.
“I know staff are under pressure,” he says, “but this is about doing the basics right. They failed Oli.”
Additional reporting Nat Wright