Just two-thirds of patients who arrived at accident and emergency at the Royal Devon University Healthcare Trust last month were seen within four hours, new figures show.
The NHS standard is for 95% of patients to be seen within four hours. However, as part of a recovery plan, the health service was aiming for 78% of patients to be seen within this time frame by March.
This was not met, with 75% of patients in England seen within four hours in A&Es last month.
The NHS England figures show there were 18,292 visits to A&E at Royal Devon University Healthcare NHS Foundation Trust in March. Of them, 12,217 were seen within four hours – accounting for 67% of arrivals.
This means the trust also fell below the recovery target and the original standard.
Across England, 46,766 emergency admissions waited more than 12 hours in A&E departments from a decision to admit to actually being admitted – an improvement from 47,623 the month before.
However, the number waiting at least four hours from the decision to admit to admission rose slightly, standing at 133,957 in March, up from 131,237 in February.
At Royal Devon University Healthcare NHS Foundation Trust, 1,688 patients waited longer than four hours, including 215 who were delayed by more than 12 hours.
Sarah Scobie, deputy director of research at the Nuffield Trust, said: "Last week we revealed that just 19% of the public were satisfied with A&E services and today's figures give us an understanding of why."
She added the number of people waiting over four hours is "astonishing".
She said: "This is 74,447 higher than before the pandemic (March 2019) and shows just how commonplace these previously unthinkable events have become for A&E patients."
She also warned the Government's plan to restructure the health organisation risks distracting from the changes patients "will directly feel the benefit from".
About 2.4 million people attended A&E departments across England last month.
The overall number of attendances at A&E at Royal Devon University Healthcare NHS Foundation Trust in March was a rise of 14% on the 15,988 visits recorded during February, but 2% lower than the 18,607 patients seen by the trust's two predecessors in March 2023.
Professor Sir Stephen Powis, NHS national medical director, said: "Despite services facing the busiest March ever in A&E and for ambulance incidents, staff continue to bring down waits for urgent and emergency care, but we know there is much more to do to reduce waits and delays across all NHS services.
"We continue to ask anyone noticing worrying symptoms or in need of care to come forward for all important checks."
Health and Social Care Secretary Wes Streeting said: "Through this government's Plan for Change, we are starting to see a real difference. Fixing our NHS is a long road, and this is just the start – but we're doing the work and delivering for patients."