More than 500 A&E patients at Bedford Hospital Trust waited four hours or longer to be admitted, transferred or discharged in December, figures show.
While this was an improvement on the same month in 2017, health bosses warned the worst of this winter could still be to come.
There were 6,185 emergency attendances at Bedford Hospital NHS Trust in December.
Of those, 532 patients waited more than four hours to be admitted, transferred or discharged.
The NHS’s target is for 95% of patients to be dealt with in four hours, but at Bedford Hospital trust, it was 91%.
This was better than December 2017, when 85% of patients were seen within four hours.
Across England, the number of patients waiting more than four hours reduced from 292,860 in December 2017 to 270,171 last December – despite overall attendances increasing.
Dr Nick Scriven, president of the Society for Acute Medicine, said: “There is more demand on the NHS, but that is something those of us on the frontline have been warning of for some time, and it cannot become an acceptable rationale for poor performance.”
An NHS spokesman said: “Thanks to the hard work of NHS staff, monthly figures show the health service performed better for A&E services this December, than December 2017, despite successfully caring for 3.9% more people within the current four-hour target.”
The East of England Ambulance Service, which covers 19 Clinical Commissioning Groups in the East of England, helped 664 patients who had an initial diagnosis of stroke.